Guatemala has become the fourth Latin American to reject all U.S. military assistance in anger over U.S. criticism of its human rights policies.

Lucy Wilson Benson, under secretary of state for security assistance-designate, said yesterday that Guatemala has joined Brazil, Argentina and Uruguay by rejecting the military assistance, totaling $2.1 million, earmarked for it in fiscal year 1978.

Benson received a series of hostile questions from members of a Senate appropriations subcommittee who made it plain they were not pleased by her answers and those of Robert H. Nooter, assistant administrator of the Agency for International Development.

Subcommittee chairman Daniel K. Inouye (D-Hawaii) and Sens. Richard S. Schweiker (R-Pa.), J. Bennett Johnston (D-La.) and Patrick J. Leahy (D-Vt.) all attacked the administration's proposal to earmark $100 million to aid southern Africa toward majority rule.

"I can't image this committee giving that kind of money" without knowing the purpose more precisely, Johnston said.

In response to repeated requests to explain how the $100 million would be used, Nooter said that it might be needed to help in Rhodesia after a transfer of power there to blacks.

Inouye asked whether the State Department would commit itself not to spend any of the $100 million without coming back to his subcommittee for approval.

Benson said she would check whether that assurance could be given. She promised to consult, but Inouye angrily rejected consultations as inadequate and blasted the State Department for failing to notify him of its emergency aid airlift to Zaire.

"If you cannot assure us prior approval," Inouye said, "I can assure you that this committee will not approve your $100 million."

The money is the first request to Congress for what former Secretary of State Henry A. Kissinger said might amount to "several hundred millions of dollars" for guarantees to white Rhodesians. The payments were part of Kissinger's intense 1976 effort to head off major racial warfare.

Earlier yesterday, Secretary of State Cyrus R. Vance told the House International Relations Committee that the $100 million is "a means of helping bring about a settlement in Rhodesia. Whether it would be used for that purpose depends on whether we achieve a Rhodesian settlement."

The fiscal year 1978 military security assistance program, which must be approved by Inouye's subcommittee, also came under attack for proposing $10 million in aid for Jamaica and because of confusion over the Carter administration's linkage of human rights and military assistance.

When Benson defended the Jamaica aid on the grounds of the island's serious economic problems, Schweiker asked what that had to to with security supporting assistance.

Schweiker said that Cubans are training the Jamaican security forces and, citing his experience on the Senate intelligence committee, called that "the code word."

"Who's training whose police," Schweiker said, "that's the whole key."