The leader of the Khmer Rouge forces of Cambodia, Khieu Samphan, wound up state visit today designed to display China's continued support for his reorganized insurgent movement and advertise his appeal for help from the Western world.

At a press conference in Peking's Great Hall of the People, attended by at least a hundred foreign and Chinese journalists, Khieu said that "all peace-loving and justice-loving countries ought to realize that it is in their own interest to stop Vietnamese and Soviet expansionism" in Afghanistan and Cambodia. Khieu left today for North Korea, after a three-day visit that included front-page Chinese newspaper coverage, meeting with Chairman Hua Guofeng and Vice Chairman Ding Xiaoping and warm banquet toasts. They signal Peking's support and, more important, its apparent best bet for keeping the Vietnamese distracted in Southeast Asia. "The Chinese government and people firmly support the Kampuchean people in their just struggle against Vietnamese aggression," Hua said in a toast at a state banquet Sunday night. We will continue to do so until they win final victory."

The Chinese appeared to be buoyed by reports from Cambodia that Khieu's forces, numbering no more than 25,000, have been able to fight off an estimated 200,000 Vietnamese troops occupying their country.

The continued Khmer Rouge survival makes it less necessary for the Chinese to turn to the mercurial Norodom Sihanouk, now visiting the United States and Canada in search of support for his own nationalist forces.

At today's press conference, Khieu made his own appeal for aid from the West.

He said his forces could survive what he said would be one last Vietnamese effort to crush the insurgents before the rainy season begins, but "we need all kinds of aid if we are to carry on and unite and mobilize all the nationalist forces against the Vietnamese aggressors. We need every form of political and material aid, weapon, medicine and foodstuffs."

He said it was difficult to move weapons into Cambodia to supply his forces. Asked how he did it, Khieu said: "We have 450 kilometers of seacoast and I can say that the Vietnamese Navey is not as strong as the U.S. Seventh Fleet."

Khieu's visit appears to be part of an organized diplomatic offensive, including recent interviews with foreign journalists as his headquarters near the Thai-Camobodian border, the Khmer Rouge a more human image and encourage support from abroad.

When asked how many Cambodians his government had executed the three years it ran the country before the Vietnamese invasion, Khieu denied that his forces followed a policy of mass killings as charged by the Vietnamese and several Western critics. He said only that there had been some "shortcomings" shortly after his forces captured the country from U.S.A.-backed forces in 1975.