The Carter administration, in what is likely to be interpreted as a signal of approval of the South Korean strongman, Gen. Chon Doo Hwan, has decided to permit the return to Seoul of the U.S. military commander there, Gen. John A. Wickham.

After attending a commanders' conference in Norfolk, Wickham has been sitting in Honolulu for more than a week as a Korean governmental shuffle prepared the way for Chon to take over that country's presidency.

Wickham's activities are particularly sensitive because of an interview he gave to American journalists Aug. 7, suggesting U.S. support for a Chon presidency. Wickham had asked that the remarks not be attributed to him by name, but he was identified as the source by Chon and his remarks widely quoted in the controlled Korean press.

Wickham's statements supporting Chon were out of step with official U.S. policy at the time, and drew public criticism from the State Department. By keeping Wickham in Hawaii rather than permitting him to return to Seoul, the administration sought to convey the message that his remarks were out of turn, and to avoid further use of Wickham's presence by Chon as a symbol of U.S. endorsement.

The decision to permit Wickham to return in the next several days was made at the general's request after a lengthy telephone conversation between him and Assistant Secretary of State Richard Holbrooke. Wickham is reported to have been anxious to participate in a previously planned U.S.-Korean military "command post exercise," codenamed "Ulchi Focus Lens 80," which is to end next Tuesday.

While seeking to avoid conveying an endorsement of Chon, the administration has sought to avoid any sign of lessening U.S. military support for South Korea, where 40,000 American troops and a longstanding security commitment remain.

Failure to permit Wickham to return for the military exercise, especially in view of his own recommendation that he participate, could have generated criticism on grounds that security was taking second place to political considerations.

The decision to authorize Wickham's return came as a top Korean emissary made the rounds of policymakers here seeking to explain the political changes under the Korean capital. The emissary, Choi Kwang Soo, is secretary-general of the presidency in Seoul.

According to U.S. officials who have talked to Choi, Chon is likely to be formally elected president by an assemblage of elders, the National Conference for Unification, by Sept. 1.

A substantial part of the recent Washington-Seoul dialogue has concerned the opposition political leader, Kim Dae Jung, now being court-martialed on sedition charges in Seoul.

The United States and other nations have asked for a fair and open trial for Kim, and appealed to the Seoul authorities not to execute Kim if he is found guilty.

The Korean leaders, according to an informed U.S. official, have sent several "informal messages" that Kim will not be executed. American officials, however, said they had not accepted such assurances as conclusive.