Sen. Edward W. Brooke (R-Mass.) admitted yesterday that he "lied" about his personal finances in a sworn deposition taken in his divorce lawsuit last year, but the senator claimed it was done to keep a family matter private.

"I lied because I did not want to bring the private matter of my family out at the time," Brooke told an afternoon press conference, attempting to explain conflicting versions which he has provided of a $49,000 private loan.

The Boston Globe revealed yesterday that the senator's divorce testimony, taken last May, attributed the loan to his old friend, liquor distributor Raymond Tye, but Brooke failed to report the loan on his financial statement submitted to the Senate.

Brooke, in private interviews, gave Globe reporters several conflicting explanations of the discrepancy, but this afternoon he offered a totally different one - $47,000 of the debt was money which he said his late mother-in-law entrusted to him before her death, and only $2,000 was a loan from his friend Tye.

Brooke claimed that the family was familiar with the status of the money and he concealed it only to prevent public knowledge of private family affairs. "I did a misstatement and a mistake and I apologize for both," he said.

The sentator is up for reelection this year and suggested that the Globe's story was inspired by members of his own family, specifically his daughter Remi. "There is an axe that is being ground," he said. "This has been peddled all over town."

By whom? "My family," the senator answered "Yes, my daughter."

Brooke's divorce settlement with Mrs. Remigia Brooke of Newton, Mass., was made final last December, ending 30 years of marriage, though the couple had been estranged for many years prior to the divorce. Brooke said yesterday they had not lived together "as man and wife" for 16 years.

The controversy left several unsettled questions. If Brooke received $47,000 from his mother-in-law as a personal loan, one which the other family members knew about, he would still be required to report it presumably to the Senate. Any loans over $2,500 must be reported, under the Senate's code of ethics. Thus, Brooke's claim that Tye only lent him $2,000 would make that personal loan exempt.

However, some of Brooke's comments to the Globe suggested that he was attempting to inflate his financial liabilities and, thus, hold down the divorce settlement. Mrs. Brooke, in the final decree, was given two homes and $18,000 annual alimony, but later filed unsuccessfully for a new hearing on the settlement terms.

Neither Mrs. Brooke nor her attorneys were available for comment yesterday. One unanswered question is, if Mrs. Brooke knew about the status of her mother's money and there was no dispute over it, why the senator would not simply list it among his liabilities.

The money, he said yesterday, was the remainder of a $100,000 insurance settlement from an auto accident which left his mother-in-law parapalegic. At one point, Brooke said he was holding the money for the family. At another point, he "owed" the money to the family and would repay it.

To date, Brooke said, he has disbursed about $17,000 of the money for his mother-in-law's medical and funeral expenses and also sent Christmas checks of $1,000 each to famuly members, as she had done when alive. His mother-in-law died last year, after Brooke's testimony, but before the divorce decree.

In his earlier explanations to the Boston Globe, before he revealed the family aspects of the money, Brooke said he was under "tremendous pressure" to settle the divorce case which was damaging his public reputation.

The Globe reporter asked: "Why did you do it? Why did you say it (the $49,000) was from Ray Tye?"

Brooke replied: "Well, one of the probable reasons was that my wife knew that Ray Tye was a dear friend of all of us and that she'd probably figure, you know, that who else could loan me that much money, to tell the truth."

But yesterday Brooke described the $47,000 this way: "The money was under my control which I discharged at the wishes of my mother-in-law."

The Globe suggested that he might be guilty of perjury, which Brooke vigorously denied. A former attorney general himself, Brooke insisted that the statement was materially correct in accounting for his debts, though he concealed to whom it was owed.

"I had always intended in my head and heart to pay the money back," the senator said.

Brooke repeatedly referred to the problem as a "misstatement," though he slipped once at the press conference and conceded that "I lied."

During his questioning by the Globe he pleaded:

"I made a misstatement. What more do you want me to say? It was not a fact. It was not a fact, obviously."

Brooke has a conservative opponent for the Republican nomination and three Democrats - Rep. Paul E. Tsongas (D-Mass.), State Reps. Elaine Nobel and Michael J. Connolly, both of Boston - are seeking their party's nomination to oppose him.

Until now, the Senate's only black member has been regarded as in a strong position to win a third term. He insisted yesterday that the new controversy would not do serious damage.

"I don't believe this mistake," he said, "will cause the people of this commonwealth or the nation to lose confidence in me."