After years of tight travel restrictions, Chinese have suddenly begun to move around their country by the hundreds of thousands, jamming newly expanded airports, railroad stations and overnight lodgings.

Recent travelers to China returning here report long lines at such tourist attractions as the Great Wall. They say workers are being allowed, apparently for the first time, to seek new jobs in distant cities. One Hong Kong editor, recently returned from Peking, said an official revealed that the Chinese capital now has about 100,000 visitors at any time and plans to increase that to 400,000 in the next two years.

The apparent relaxing of travel restrictions has occurred during the year since the death of Chairman Mao Tse-tung and the rise of a new pragmatic leadership pledged to improve living standards. A new accent on consumerism "may explain in part the new policy," said David Chen, foreign affairs editor for the South China Morning Post, who visited both Peking and Shanghai recently.

"Trains, public vehicles and riverboats" are jammed, said Chen, who last visited China four year ago.

"Air transport is also congested, with increasing numbers of cadres of relatively junior rank traveling by plane."

Greater numbers of visiting foreigners, particularly those of Chinese descent, have helped swell the crowds traveling between cities. A Hong Kong businessman travel reflected the new Peking administration's desire "to show people how much has been accomplish" since its more dogmatic opponents in the Communist Party were purged in October.

Apparently to ease the way for travelers, the official Chinese press has encouraged improvements in train service by praising railway worker achievements "in a period of rising train travel and a speeded-up tempo of both freight and passenger traffic," according to a June 30 New China News Agency dispatch.

The Chinese say they will build at the airport two new parking ramps with space for 16 large aircraft, and a six-story hotel for foreigners. They have already built a second runway and lengthened for the original runway to 12,500 feet.

Peking reported April 15 that it had opened a new 2,160-mile air route between Shanghai and Urumchi, in the far west, making it the longest air route in the country.

On July 1, the New China News Agency reported the opening of a new railroad station in Changsha, in central China, important because it is the nearest city to mao's birthplace in Shaoshan, a favorite Chinese tourist stop.

The new station, equipped with computers and closed-circuit television, can accommodate 6,000 passengers at a time, making it second only to Peking's station in size.

The huge Peking station is a noisy beehive day and night, full of soldiers, government officials and families with children. The same kinds of people can be seen having their pictures taken daily in Peking's famous Tienanmen Square. American journalists who accompanied Grace Vance, the wife of the U.S. Secretary of State, to the Great Wall of China last month had to leave their cars before they got to the parking lot because of a crush of buses bringing Chinese sighseers from Peking.

Chen, the Hong Kong editor, said he was startled to find on his most recent trip that workers unhappy in one city were being allowed to move elsewhere if they could find aworker to swithch jobs with them.

Chen said he was notices on city lamp posts seeking such switches.

Many of the Chinese travelers appear to be officials and workers who have, less money and fewer distant contacts to allow such travel.

The last great spurt of unrestrained travel in China occured during the great Cultrual Revolution of the late 1960s, when the schools were closed and young Red Guards were encouraged to travel about the country free of charge to exchange revolutionary experiences. The Chinese railroad system nearly broke down under the weight of young travelers. Peking is not expected to let travel restrictions become so loose ever again.

Much of the increased travel now, some observes say, may be traced to the unusual number of national conferences and celebrations that have been held in Peking lately. In their newly centralized economic system, Peking officials may also be calling provincial administrators to the capital more often for consultations.

Some of the expanded air facilities are also designed for what Peking apparently hopes will be increased overseas business for the national airline, the Civil Aviation Administration of China. An airline delegation held talks in June with Ethiopian officials over opening service to African countries, seven other Communist countries, sand Japan, Burma, Pakistan, Iran and France.

Its fleet includes Soviet aircraft, British Tridents and 10 Boeing , 707 believed to be under-used. But foreign travelers have complained of the airline's spartan service, which provides, in the words of one American traveler, "no lunchesand no toilet paper in the ladies's room."