A Soviet cosmonaut, using a new, more flexible spacesuit, walked in space for 20 minutes today to check the primary docking port of his orbiting Salyut 6 station.

The walk by flight engineer Georgi Grechko, the first by a Soviet spaceman in nine years, went off without a hitch. Grechko, attended by station commander Yuri Romanenko, reported that the docking unit is in apparently perfect condition. The docking unit was said to be the cause of an earlier unsuccessful attempt by another Soyuz to link with the Salyut lab two months ago.

Grechko's report may be crucial to the Soviets, who reportedly may try to send another Soyuz ferry craft to the space station to join the present twoman crew.

Tass, the official Soviet news agency, said Grechko and Romanenko spent the previous two days in the Salyut "occupied with the forthcoming operation. They checked the space suits and tried out their life support systems. Exactly at midnight, when both had already put on the suits and reduced pressure in the transfer compartment virtually to zero, (mission control) granted permission to open the hatch. Grechko emerged into outer space as Romanenko assisted."

Grechko was to attempt repairs if the docking unit was damaged, but he reported that "all the equipment is in full working order. The receiving cone is also clean, without a single scratch."

Grechko panned around the exterior of the space lab showing parts of the solar panels that supply electricity to the lab, and the earth moving in the background. In all, said Tass, the two men spent 88 minutes in the near-vacuum conditions of space, of which most apparently was spent depressurizing and then repressurizing the transfer compartment leading to outer space.

It is thought here that the Soviets are more interested in perfecting their space systems than in setting any endurance records in space. The Salyut space station project, centerpiece of the Soviet space effort, has been plagued with troubles. A number of Salyuts, and other crews' attempts at long-term living once aboard have fallen short of the 1974 American record of 84 days in space aboard a skylab.

The new spacesuit used by Grechko and Romanenko has a small instrument panel in the front and a door-like entrance hatch in the back. The arms and legs have greater flexibility than previous Soviet spacesuits.