SEATTLE (AP) _ Jockey Jody Davidson, 23, of Vancouver, has been suspended ''permanently'' by the state Horse Racing Commission because he twice was tested positively for marijuana use.

The commission took its action at a meeting Wednesday.

However, Commission Executive Secretary Bill Aliment said Davidson, 1981 Longacres riding champion, could reapply to the commission for a jockey's license if he successfully completes a drug rehabilitation program.

''So 'permanently' doesn't necessarily mean 'permanently,' '' he said.

Davidson has the right to make a Superior Court appeal but neither he nor his lawyer, Bob Kuvara, have indicated they would do that, Aliment said.

Aliment said Davidson was tested positively for marijuana use at the 1985 Longacres meeting and given a 30-day suspension by the Board of Stewards at the thoroughbred track.

Davidson was tested positively for marijuana use Dec. 5 by the Portland Meadows Board of Stewards, Aliment said.

''This sport is dangerous enough without a jockey's senses being impaired,'' he added.