The House yesterday voted 241 to 167 to prohibit the Legal Services Corp. from bringing class-action suits against the federal, state or local governments on behalf of poor people.

Although only 1 percent of legal-aid suits are class actions -- cases that represent a number of plaintiffs on the same issue -- they have caused "90 percent of the trouble," according to Rep. Charles Wilson (D-Tex.), who sponsored the amemdment.

Wilson said his class-action amendment is necessary to prevent Legal Services' $260 million, funding bill from being voted by President Reagan. Reagan wants to transfer responsbility for poverty law in civil cases to state government and bar associations.

Wilson's amendment was a critical victory for conservatives who say legal aid funds have been used by activist lawyers to further liberal causes. One class-action suit was brought in his district, Wilson said, to prevent the deportation fo illegal aliens.

Arguing against the amendment, Rep. Robert W. Kastenmeier (D-Wis.) cited testimony in the Judiciary Committee by Maryland's attorney general praising legal aid attorneys for bringing class actions on unemployment compensation, Medicaid, veterans' benefits and mental patients' rights. Kastenmeier quoted the attorney general as saying that the suits "indicated the rights of thousands of poor citizens in the state of Maryland."

Massachusetts Democrat Barney Frank called the amendment "blatant discrimination." It says, he added, "If you represent poor people we're going to tie one hand behind your back."

Millicent H. Fenwick (R-N.J.), however, said poor people are already represented in class actions by public defender offices in her state and that Legal Services attorneys should concentrate on marital, landlord-and-tenant, commerical and other cases of that sort.