Former vice president Walter F. Mondale charged yesterday that President Reagan's policy on Central America makes it inevitable that U.S. troops will be sent to fight in El Salvador.

"I believe this country is widening the war. I believe it's Americanizing the war. I think it's militarizing the war. And I believe under present policies, it is inevitable that American troops will be sent into Central America because the policy is failing," Mondale said on "Meet the Press" (NBC, WRC).

Mondale's statement came after he was asked if there were circumstances under which he, as president, would send U.S. combat troops to Central America. He said the presence there of a major Soviet or Cuban base or military position would be a "very, very severe concern" but did not say whether he would send troops. "We're raising a hypothetical here. Let me talk about the real world and what's going on today in Central America," he said.

Generally considered the front-runner among announced Democratic presidential candidates, Mondale said the administration views any political or military action in El Salvador as a threat to U.S. security. He acknowledged that there were problems in Central America while he served in the White House.

"But it wasn't a crisis," he said, adding that the Carter administration "was pressing El Salvador and others to move toward the respect of their own human rights, toward a system of justice, toward land reforms, toward working with the church, with the Social and Christian Democrats to create an environment of stability . . . ."

The Reagan administration "upended it and turned it into principally a military venture with very little, if any, emphasis on political reform or on efforts to bring about a negotiated settlement," he said.

"Where they're going now will lead to the introduction of troops in any event because right now they've rejected negotiations, and they've rejected any kind of effort to bring about social and political reform in El Salvador," he said.

"It has gotten worse every day that they've been in power . . . . If anything, they're accelerating the rate . . . going full speed ahead for a military solution. And I believe . . . it's almost inevitable that American troops will be sent down there," Mondale said.

Meanwhile, President Alvaro Magana of El Salvador said that his government is winning the war against leftist guerrillas and that he is "positively sure" that U.S. troops never will be needed to ensure victory.

"Never. I am positively sure of that. Neither will they be needed, neither we are going to ask for them," he said in an interview taped Saturday and shown yesterday on "Face the Nation" (CBS, WDVM).

Disputing recent accounts of poor performance by Salvadoran military forces, Magana insisted they have fought hard and that with U.S. help, "we have better trained troops than we had a year ago and much better than two years ago. I'm sure that we have improved a lot."

In response to questioning, he said right-wing Salvadoran military officers have formed death squads to kill leftists.

"I have to accept that we have that problem," he said. "But this is difficult to control in a period like this, because we are so busy taking care of the other ones . . . . I hope, when all the violence goes down, the problem of human rights is going to be disappearing slowly . . . . Of course, in many cases the death squad had nothing to do with politics."