Gulf escalation clouds Shultz visit to Soviet Union. SUMMIT PREPARATIONS

The United States Secretary of State arrives today in Moscow for what may be the final round of preparatory talks before President Reagan meets the Soviet leader here at the end of May. George Shultz will have two days of agenda-setting negotiations with the foreign minister, Eduard Shevardnadze, and the Soviet leader, Mikhail Gorbachev, before heading south to the capitals of the Ukraine and Georgia - his first visit to the Soviet provinces.

The original agenda for the visit included the now-traditional themes of human rights, regional hot-spots, arms control, and bilateral issues. But these have been overshadowed by the past week's events in the Gulf, where the US Navy attacked Iranian oil rigs and ships after an American ship was damaged by an Iranian mine. The Soviets are expected to deliver a stern lecture to the secretary of state.

Although tension in the Gulf appears to be subsiding, the incident undermined the improving atmosphere that had resulted from the signing of the Afghan peace accords in Geneva last week. The Soviets saw the US actions against Iran as a betrayal of the principles of superpower cooperation and restraint that had allowed Moscow and Washington to come together as guarantors of the Afghan agreement.

Sources in Moscow say the Soviet leadership may be less strident in its condemnation than recent Soviet press commentary, which branded the US retaliation as ``banditry.'' But Mr. Shultz's calls for Kremlin agreement to a UN Security Council arms embargo against Iran are likely to fall on deaf ears.

While publicly adopting a neutral stance on the Iran-Iraq war, the Kremlin is anxious not to alienate Iran during the sensitive period of its troop withdrawal from Afghanistan. Iran harbors some 2 million Afghan refugees.

Substantial progress toward a strategic arms reduction agreement also seems unlikely, not just because there are still more than a 1,000 disputed points in the draft text of the treaty, but also because the urgency of achieving a deal in time for the Moscow summit seems to have evaporated on both sides. Senior diplomats on both sides say they want a ``good agreement,'' not a quick one.

On the strategic defense initiative (SDI or star wars), however, Pravda yesterday showed signs of compromise. In a commentary, Col. N. Karasev repeated the standard position that space-based defenses must be limited to what is permitted under the 1972 anti-ballistic missile treaty.

But he said it was ``an illusion'' to imagine that President Reagan's SDI program could be stopped. ``I think that much of what has been started in the framework of SDI will be developed,'' he said.