Boston Mayor Kevin H. White is considering entering the race for the Massachusetts Senate seat held by Edward E. Brooke (R-Mass.).

White, who is here attending the annual convention of the U.S. Conference of Mayors, has been consulting political advisers on the possibility for the past two days but reportedly has reached no decision. He has until July 5 to announce whether he will enter the already crowded Democratic primary field.

Brooke, a two-term veteran, had been considered unbeatable in Massachusetts, but his political standing has been severely damaged, in the view of most observers, by recent disclosures that he misstated the source of some funds in his divorce proceedings. A retrial of the divorce has been ordered and other legal actions against nim are possible.

White, who is scheduled to complete his third-term as mayor nextyear, served previously as secretary of state. However, he lost his last statewide campaign when he ran for governor in 1970.

Brooke is opposed in the Republican primary by Avi Nelson, a strongly conservative Boston talk-show host.

Several well-known Democrats, among them Lt. Gov. Thomas P. O'Neil III, took themselves out of the Senate race before the full extend of Brooke's difficulties were known.

White is reported to be concerned that the urban-oriented liberals remaining in the Democratic field may not be strong enough statewide candidates to capture the primary and defeat the Republican nominee.

But the mayor is reported to be hesitant about appearing to capitalize on Brooke's personal troubles. He is also somewhat uncertain about the prospects of serving, if elected, as a junior colleague to Sen. Edward M. Kennedy (D-Mass.).

Relations between Kennedy and White have never been close, and Kennedy was reported to have played a role in blocking White as a vice presidential running mate for Sen. George McGovern (D-S.D.) in 1972.

The Democratic senatorial field already includes Rep. Paul Tsongas (D-Mass.), Boston school committee chairman Kathleen Sullivan Alioto and state Reps. Elaine Noble and Michael J. Connally.