PESHAWAR, Pakistan--A top Afghan guerrilla leader said yesterday he believes the Soviet Union wants to withdraw its forces from Afghanistan and may be ready to sacrifice the Afghan Communist government if necessary.

Gulbaddn Hekmatyrar, head of the Hezbi-i-Islami guerrilla group and one of the most hard-line of the insurgent leaders, said that Moscow's recent statements about wanting to pull out of Afghanistan appear genuine.

He also outlined a series of demands for a settlement, including direct talks with Moscow.

The Soviet-backed Afghan government has called for a six-month cease-fire with the guerrillas beginning next Thursday and proposed forming a government of national reconciliation to end the eight-year war in Afghanistan. The Soviet Union has strongly backed the call and said it wants to remove its forces from its Central Asian neighbor.

Leaders of the seven-party guerilla alliance individually have rejected the government's proposal and said they will go on fighting until Afghanistan is free of Soviet control. The leaders, all based in Pakistan, were to meet in Peshawar today to enable the alliance to present a united response.

Hekmatyrar, in the most optimistic reaction yet by a top guerrilla leader, said strong signs have emerged that the Soviets want a political settlement.

"The Russians have realized they cannot crush the resistance. Now they are trying to solve the problem through other ways and means," Hekmatyrar said. "They have to withdraw and they have realized there is no other solution."

Western estimates are that the Soviets have lost up to 8,000 soldiers in their seven years of military intervention in Afghanistan.

The guerrilla leader, one of the dominant figures in the alliance, called for a settlement which would start with direct talks between Moscow and the insurgents on the sole subject of arranging an immediate Soviet withdrawal. The guerrillas would guarantee safe passage to withdrawing Soviet troops, he said.

"The Russians could withdraw in less than one week if they are sincere," he said.

Soviet withdrawal would be followed by formation of a provisional government acceptable to all the Afghan people, Hekmatyrar said. The provisional government would prepare for elections that the guerrillas expect would lead to creation of an independent, nonaligned Moslem republic, he said.

The new Afghan state would guarantee never to allow any other power to operate from its territory against Soviet interests, Hekmatyrar said.