The Supreme Court agreed yesterday to decide whether Congress intended to let states pay strikers unemployment insurance benefits financed by their employers.

Two lower courts were unable to determine from the history of the National Labor Relations Act precisely what Congress had in mind. They then made conflicting decisions.

The case before the Supreme Court arises from a seven-month strike in 1971-72 against the New York Telephone Co. and other units of the American Telephone & Telegraph Co. in New York State.

After a waiting period of eight weeks required by a 1935 state law, about 33,000 strikers, members of New York local of the Communications Workers of America, AFL-CIO, collected some $49 million in tax-free unemployment benefits.

The weekly maximum was then $75 per person. Currently, it is $115, and in September it will increase to $125. Employers pay the entire bill.

The New York employes of the Bell System walked out as part of a nation-wide strike against AT&T. After about a month, however, strikers everywhere else returned to work. The New Yorkers continued to strike - illegally, the National Labor Relations Board held - about six months longer.

New York Telephone attacked the 1935 law in a lawsuit in U.S. District Court. Ruling for the company, Judge Richard Owen said the law's benefits substantially affect workers' willingness to strike or remain on strike, tip the economic scales in their behalf, and force New York employment benefits program, to subsidize lengthy strikes against themselves.

The key issue was whether the unemployment benefits conflicted with the labor relations act - which Congress enacted two months after adoption of the state law - and therefore viloated the provision of the Constitution that makes federal law supreme.

Owen held the benefits unconstitutional to the extent that they were a strike subsidy, but was reversed in November by the 2nd U.S. Circuit Court of Appeals.

Congress has been aware of the New York law for more than 40 years, but never expressed an intent to preempt any such laws, Judge Thomas J. Meskill wrote for the appeals court. "Therefore, the conflict between New York's statute and and the broad federal policy of free collective bargaining does not render the state statute unconstitutional. The conflict is one which congress has decided to tolerate."

Similarly, the Justice Department said two years ago that Congress "elected to leave this matter to the judgment of each state."

In 1973, however, the 1st U.S. Circuit Court of Appeals, while finding a lack of "unambiguous congressional intent," invalidated a Rhode Island law similar to New York's.

In its successful petition for Supreme Court review of the 2nd Circuit Court decision, New York Telephone compalined of "increasing" use of unemployment benefits "as a strike weapon to complement or replace the unions' own strike funds."

New York State, however, said that the long strike had reduced the company's net payout for wages by $86 million whiel yielding a contract nearly identical to the one originally offered. And, it said, strikes are of shorter average duration in New York than elsewhere.

In a friend-of-the-court brief, the Chamber of Commerce of the United States argued that by reducing the waiting period for benefits and increasing their size, states could "easily crush employer resistance" to strikes.

The court took other actions: EMPLOYE TESTS

In a second federal labor-law case in which arguments will be heard next winter, the court agreed to review a decision that, when callenged by a union, an employer must supply it - on a confidential basis - with copies of aptitude tests and results used to select employes for promotion to skilled jobs.

The 6th U.S. Circuit Court of Appeals made the decision in a case involving the Detroit Edison Co. of Michigan and the Utility Workers Union of America Inc.

The American Psychological Association charges, but the government denies, that the decision threatens the confidential relationship between psychologists and their clients, in this case, the company and the employes. CHINESE FIRECRACHERS

Chinese-Americans continuing ancient traditions, use firecrackers for what the Consumer Product Safety Commission calls "necessary" religious purposes. But, the commission ruled in 1976, they will have to forgo the bang of big crackers because they are unsafe. Like everyone else, the Chinese-Americans will have to make do with "ladyfingers."

The state of Hawaii protested the lack of evidence that ladyfingers will satisfy Chinese religious needs. The Court of Appeals ruled for the District of Columbia. The Supreme Court let the ruling stand.