In a move with potential military significance, China said today it will launch its first permanently orbiting communications satellite this year.

The announcement came in the Communist Party newspaper People's Daily, which said the chief purpose of the geostationary satellite would be to experiment in telephone communications as well as television and radio broadcasting.

Foreign experts here said a successful launch would be a major technological breakthrough that would improve communications in all facets of China's life, including the far-flung military.

It also could have implications for China's fledgling nuclear force, western military sources said. The rocketry needed to propel the satellite into orbit--a three-stage launcher--far exceeds the firing power of the nation's current intercontinental ballistic missiles.

Only the United States and Soviet Union have mastered the technology to boost and properly position a communications satellite 23,000 miles above the earth, industry sources said.

A few years ago, Peking had considered buying a $200 million satellite communications system from the United States, but the plan was scrapped because of economic difficulties. According to industry sources, China managed to acquire detailed technical information--including drawings and specifications--from U.S. companies bidding for the contracts. It was not clear, however, whether this information contributed to the program announced today.

"If they can actually get a satellite into geostationary orbit, they're playing in the big leagues," said a western expert. "It would represent a real quantum jump and would create quite a stir outside China."

A geostationary satellite, set at a fixed position relative to the Earth, relays signals from different points on land. It is used for telecommunications, not data gathering or spying.

China has launched 12 satellites since 1970, but none has had the sophistication of the planned space shot. The earlier models all returned to earth after achieving an altitude of less than 500 miles. Scientists here have been known to be working on a permanently orbiting satellite for years, but they were not expected to begin testing until late 1985.

People's Daily said in the two-paragraph bulletin that the satellite would remain fixed at the longitude of 70 degrees East, over the Indian Ocean. No date was given for the launching.

Industry sources said the satellite would vastly improve communications for the world's largest Army, which now is linked by a rudimentary and fragmented telephone network. Millions of troops dispersed along China's extensive frontiers rely on radios that are vulnerable to weather changes and open to enemy monitoring.

The satellite could provide a reliable and private channel for the military in its most remote outposts, the sources said.

"They aren't much beyond the flag-waving stage today," said a foreign expert. "The satellite would bring Chinese military communications from the Middle Ages to the late 20th Century."

The importance for China's nuclear weapons program would be less immediate, according to military analysts. A successful shot would mean scientists have developed a three-stage propulsion system. The ICBMs test-fired in 1980 with a range of 6,200 miles were launched with two-stage rockets. But China is still thought to be years away from perfecting the guidance system and electronics to match the precision and range of U.S. and Soviet missiles.

"Even if they have the physical capacity to chuck something far, it doesn't mean they can make it go where they want," explained a military source.

The three-stage satellite launcher is expected to be powered by liquid fuel, which is not used in the U.S. space program. Although a successful launch would mark a new milestone in liquid-propellant technology, the fuel is considered dangerous and bulkier than the solid alternative used in the U.S. space program.

In addition to its military application, the satellite is said to have great potential for helping authorities communicate with areas stricken by earthquakes or floods when normal telephone lines would be out of operation.

With China planning to explore for oil off its continental shelf, the satellite also could provide easy communication to shore.

If China succeeds in the ambitious plan without foreign assistance, the exploit could be used by the ruling faction as a powerful political weapon against leftist opponents who criticize the current, relatively open-door policy as a bartering away of the Communist Chinese tradition of self-reliance.

Leftists in the Army reportedly have resisted efforts to modernize the defense sector with expensive foreign imports.