Nearly 36 percent of all blacks lived in poverty last year, the highest black poverty rate since such record-keeping began in 1966, according to a report released yesterday by a nonprofit public policy group.

The Center on Budget and Policy Priorities, which has provided much of the statistical underpinning for criticism of the Reagan administration's tax and budget policies, said these and other figures show that blacks are worse off today than they were in 1980.

Coming a month before the presidential election, the report was seized on by black leaders as political ammunition. The center is headed by former Carter administration official Robert Greenstein.

"Certainly, 36 percent of blacks falling below the poverty line clearly shows that these policies are not working for black Americans, and black Americans are not better off now than they were four years ago," said Rep. Julian Dixon (D-Calif.).

The report -- based on data from the Census Bureau, Congressional Budget Office, Bureau of Labor Statistics and other sources -- says the gap between blacks and whites, as well as between rich and poor, has widened considerably because of administration policies.

Black middle-class families, as well as blacks in poverty, have a lower standard of living today than in 1980. Hardest hit, according to the report, were two-parent black families in which one parent worked and the other took care of children.

The income of the typical black family fell 5.3 percent after inflation from 1980 to 1983, a reduction of $818, the report said. By contrast, it found that income for the top 60 percent of the white population gained considerably.

One of the report's bleakest findings concerned those who have been out of work at least six months and are still looking for work. While the number of whites in such straits has risen 1.5 percent since 1981, long-term unemployment among blacks has risen 72 percent.

During the economic recovery, overall black unemployment has slowed at a substantially slower rate than has joblessness among whites, according to the report.

From 1980 to 1983, an additional 1.3 million blacks fell into poverty, the center found. Nearly half of all black children, over half of blacks living in female-headed households and over one-third of elderly blacks now live in poverty, the report said.

In addition, it said, the already large gap between black and white poverty widened further. It found the proportion of blacks who have joined the poverty rolls since 1980 is almost double that of whites.

The center also found the tax burden has been shifted from whites to blacks as taxes have been raised for lower-income families and sharply reduced for the most affluent. The reason, the report said, is that most blacks are among the nation's poorest 40 percent.

The report also said that administration cutbacks have cost the average black family three times as much in lost income and benefits as the average white family.

M. Carl Holman, National Urban Coalition president, said such findings are being ignored in the presidential campaign. "People who raise questions [about black poverty] are treated as though they are whining," he said.