The People's Republic of China, in its first major venture with a foreign broadcaster, has signed an agreement with CBS Inc. that will bring American commercial television to the mainland's airwaves by October.

The agreement calls for CBS to provide China Central Television, the PRC's national network, with 64 hours of programming in the first year. According to John Eger, vice-president and general manager of CBS International, CCTV will air a weekly hour of CBS programming on Friday nights plus semi-monthly half-hour specials on Sundays following the Chinese network's English-language lesson programs.

Although China has purchased selected American programs in the past, this is the first agreement for a continuing supply of programming.

The precise content of the weekly shows will be determined after evaluation by CCTV officials coming to America later this month.

Charles Walsh, CBS International's advertising sales director, said, "They seem very interested in NBA and NCAA basketball, a series we've done on World War I and a mini-series on Ben Franklin, who they like because he's seen in China as a revolutionary."

In what may perhaps augur a different sort of cultural revolution, CCTV has agreed to let advertisers sponsor the shows. "That's the really crucial thing," says Eger. CBS will be allowed to sell five minutes of commercial time per hour and then split the proceeds with CCTV.

Walsh said that CBS International will sell time to a "select group of ten multi-national sponsors" at $300,000 each. No deals have been signed although discussions with such companies as Coca-Cola Co. and American Motors Corp. are reportedly under way. Advertisers may choose to tailor their ads to the Chinese market in anything from 15-second spots to five minute image-building "infomercials."

CBS and CCTV "will co-operate in several other areas, including current and new broadcast technologies and possible joint venture production efforts in China and elsewhere," said Eger, who headed the White House Office on Telecommunications Policy in the Nixon administration. CBS International will also help CCTV market its programming in the United States and in other countries.

CCTV reaches more than one-third of China's more than one billion population with two channels of programming in all but one province. There are roughly 30 hours of programming a week including news, sports and education.

Despite China's enormous population, television sets are relatively scarce. One source puts the number somewhere between 15 to 16 million with a third of that number, says Eger, being distributed last year. If current policy is any indication, Eger expects explosive growth of television on the mainland. However, he is reluctant to predict the future of commercial television there.

The CBS announcement reflects an increasing awareness by U.S. broadcasters of the international television market. CBS International, which is two years old, has been attempting to forge "associate" relationships with broadcasters in other countries as a counterpart to the CBS domestic network's affiliates.