The Washington Star, now an evening newspaper, plans to begin publishing an early-morning edition for street sale beginning Monday, July 9, according to announcements made yesterday to the newspaper's employes.

Press start for the new edition reportedly would be 3:30 a.m., about six hours earlier than current press time for The Star's first edition. Plans call for the new edition to contain late sports results and other late night news, and to be available by 6 a.m. in vending machines throughout the area inside the Capital Beltway.

The possibility that The Star would print an early-morning edition had been widely discussed in newspaper circles since the 127-year-old daily was acquired last year by Time Inc. The Star was losing money at the time of the purchase and an early edition was viewed as a possible means of closing the circulation gap between it and The Washington Post, a morning paper.

Monday to Friday circulation of The Post in the six months ended March 31 was more than 598,000 compared to a figure of more than 340,000 for The Star.

Executives of The Star and of Time Inc., who could be reached last night had little or no comment in response to questions about the new edition.

"I can't give you a thing," said Murray J. Gart, editor of The Star. "We'll have our announcement in the paper tomorrow . . ."