AFL-CIO President Lane W. Kirkland said last night the Treasury Department's new income tax proposals would do "serious and unnecessary harm" to many working Americans by taxing all unemployment benefits and imposing new taxes on workers' compensation and on some health benefits.

"You are loading a burden on the people least able to bear it," Kirkland said, referring to the plan to tax all unemployment payments, instead of the current tax, which applies only to benefits that put family income above $18,000.

"And taxing people who are injured on the job is simply totally wrong," he said.

Ending the tax-free status of employer-paid health insurance above a certain level would also seriously disrupt collective bargaining between unions and employers and would in effect "load still another tax" on many of the 20 million union workers, he said.

Kirkland made his remarks at a press conference preceding a speech at the University of Maryland, which last night named its labor studies program in honor of the late Thomas W. Bradley, president of the Maryland-D.C. AFL-CIO, who died last year.

Kirkland, who has been highly critical of the Reagan administration for what he calls biases favoring the rich and big business, said there were some "positive aspects" of the tax proposals, such as ending the oil-depletion allowance and reducing corporate tax credits that companies receive for taxes paid to foreign governments.

But he predicted those facets of the complex tax package may not survive. "All of our experience tells us when you are up against a hostile administration, a mixed-bag Congress, there is a strong possibility that what's good in the tax plans will be lost and what's bad will remain."

Overseas tax credits "subsidize American companies for locating their production overseas instead of here," which in effect threatens American jobs, he said, while the oil allowance benefits some of the world's richest firms.

"I have doubts whether this taking-away of goodies from rather powerful forces in our society will survive" the legislative process, he said.

In his speech to a gathering of labor leaders, politicians and university officials, Kirkland praised Bradley's efforts to improve education, especially for working people.

But he was critical of the educational establishment for failing to give more prominence to problems in the workplace and the role of unions.

"Working people need and deserve more attention than they get from the schools and universities they support, including this one," he said. "Too many schools have been content to treat workers as minor and even abstract factors in the equations of the economic process."

"What university offers a course in labor relations that reflects the individual worker's view?" he said.

The university labor program, named for the late Baltimore machinist who became an influential labor lobbyist in Annapolis, includes a variety of practical courses conducted for union members.