American Broadcasting Companies, Inc. followed the lead of the nation's other two major television networks yesterday in signing a proposed consent decree with the Department of Justice that restricts ABC's control over network prime-time television programming.

The decree, which could put an end to an eight-year legal battle, was filed in U.S. District Court in Los Angeles and still must be approved by the federal judge in the case.

The consent decree is particularly important because key provisions of the similar -- but not identical -- decrees filed by Columbia Broadcasting System Inc. and National Broadcasting Inc. are contingent on the ABC agreement. The CBS settlement was entered by the court on July 31, 1980, while the NBC consent was approved in November 1977.

If the networks and the judge agree to the terms of each of the complex settlements, the agreements in the case would bring to a close a bitter battle that began in 1972 when the suits against the three networks were filed.

The networks, particularly CBS, charged that the suit was an effort by Nixon administration officials to inhibit criticism. The suits were dismissed in November 1974, but were refiled one month later after Gerald Ford became president, which effectively squashed the charge that the cases were politically motivated.

The ABC consent agreement would limit to 10 years the amount of network programming that the network could produce for its own use and, in a variety of ways, would restrict the network's production and syndication rights. News, public affairs and sports shows are not part of the suits.

In addition, the ABC consent agreement also keeps the network from offering more than specified hours of programming and shows obtained from sources other than independent program suppliers.