A bitter three-year congressional fight neared its end yesterday as the House approved, 272 to 127, the conference report on a bill extending the life and spelling out the powers of the Federal Trade Commission. The Senate is also expected to approve it and send it to the White House, where President Carter has indicated he will sign it.

The fight has been going on since Michael Pertschuk moved from a Senate staff job to the FTC's chairmanship and began an aggressive campaign to protect the public from unfair and deceptive trade practices.

The industries he moved against complained to Congress, and the fight over curbing the FTC or letting it go free had been going on ever since. Now Congress apparently has settled it with a bill that extends the life of the commission for 2 1/2 years and compromises on the issues in dispute.

The House had insisted on -- and the Senate had opposed -- providing for a one-house congressional veto of an FTC industry wide regulation. The final version requires either affirmative action by both bodies to veto a regulation, or action by one body and failure by the other body to express an opposite view.

Several House and Senate provisions forbidding the FTC to regulate specified industries were modified to permit some regulation but not free-wheeling regulation.

House debate on the House-Senate conference report showed that no one was completely happy with the result, but most were willing to accept it.