Rock Hudson looks back on his films and ahead to his TV series

''The last major star to emerge from the Hollywood studio system'' (according to cinema historians) has finally succumbed to a weekly television series.

After many TV specials and mini-series - and after more than 60 movies - Rock Hudson has surrendered to the inevitability of a weekly series: The Devlin Connection (NBC, Saturdays, 10-11 p.m. - premiering tomorrow). But although ''Devlin'' is basically a formula detective action drama, Mr. Hudson and the writers manage to keep it light and caper-y, a la ''Pillow Talk'' and all those frothy and feathery Doris Day-Rock Hudson films.

Hudson plays the role of an urbane former owner of a private investigation agency, now the administrator of a cultural center, drawn back into detective work by his newly discovered son. The character is very much like Hudson himself - a mature, polished adult with a full life of experience behind him but prepared to take on new challenges.

We meet for lunch about 20 blocks from the apartment he maintains overlooking Central Park - he also has a house in the Los Angeles area (to which he plans to return in a few days to ''do a bit of remodeling'').

Today's Rock Hudson looks like a grown-up version of the black-haired romantic lead of his early career. Although he now has iron-gray hair with a matching mustache, he is still recognizable as a bigger-than-life movie star. As if to prove that, a young woman approaches our table for an autograph, evading the attempts of the waiter posted nearby by the maitre d' to prevent such interruptions. Rock signs his name pleasantly and remarks to me, ''It's like old times.''

The last film he made was ''The Mirror Crack'd'' in 1980, an Agatha Christie story with Elizabeth Taylor. If he could choose to be remembered for only one film, what would it be?

''That's a tough one,'' he says thoughtfully, and thinks. '' 'Giant,' I guess. But that was 27 years ago.''

There has been talk about doing a sequel to 'Giant' - the highly successful film based on the Edna Ferber novel - perhaps even making a series based on it, but Mr. Hudson shakes his head. '' 'Giant' was near-perfection and I wouldn't have anything to do with a sequel unless it, too, could approach perfection. But . . .'' and he shakes his head, a silent comment upon the sad state of movies today.

Most people remember him best for those charming light comedies in which he co-starred with Doris Day. ''There aren't enough of those today,'' he says. ''I'd like to do more of them. But good light dialogue is so difficult to write.''

Mr. Hudson, who has acted and sung in several musical comedies on stage, would like to do more of those, too. He appeared in ''Camelot,'' ''I Do, I Do,'' and ''On the 20th Century'' on tour. I want to do it all,'' he says - ''movies, television, theater.''

Was it difficult as an actor to make the transition from film to TV?

''It's faster for TV, that's all. Acting technique is all the same. In TV now , when the pressure is on and there's no time to rehearse or redo, I say to myself, 'Thank the Lord I have 30 years of experience to fall back on.' I don't know how the less experienced actors do it.''

According to him, ''Devlin'' still needs some developing. ''It's good, but not quite there yet. TV series take a while to settle in, find themselves. It's a very difficult show to write because the accent is on the fun in solving crimes, as opposed to whodunit. The easiest shows to write are straight crime shows. There's a murder and then a search to find the guilty party. But we deal in humor and ambivalence of character.''

Mr. Hudson watches lots of television but likes little of what he sees. ''After 10 years, there's still only 'M*A*S*H.' I believe the public wants a higher degree of intelligence in its entertainment than it gets. TV executives are afraid to give it to them.''

Co-starring with Hudson in the new series is a young actor, Jack Scalia, whom he helped choose to play the role of his son. ''We had worked together in a mini-series, 'The Starmaker,' several years ago and I got to know him as a terrific actor, a terrific guy, with no hang-ups about asking for help when he needed help.

''A lot of young actors have that problem. Originally, that role was to be a daughter, but it was changed. Now, I expect him to be as hot as Tom Selleck'' (the star of ''Magnum, P.I.,'' CBS, Thursday, 8-9 p.m.). Does Rock Hudson resent not being considered a sex symbol anymore?

He laughs loudly and displays the recognizable sparkling Rock Hudson teeth: ''I'm too old to be a sex symbol. Let Jack do all that.''

Many screen actresses, as they mature, resent the fact that women are expected to continue looking youthful while men can mature gracefully on the screen. They claim there are many more roles for older men than for older women.

Hudson shakes his head. ''It hasn't stopped Katharine Hepburn, has it?''

What would make ''Devlin'' a success in Hudson's eyes?

''Of course, popularity. We need that to keep us going. But, more than that, I'd like the show to be accepted as classy, sophisticated, educational, literate entertainment. The kind of show we see so little of in any medium these days.''

As we leave the restaurant, there's a buzz of excitement among the other diners. Whether considered a sex symbol or simply a veteran actor, Rock Hudson still represents the ''good old days'' of Hollywood entertainment for his many admirers.