While the expected lifespan of whites and black females continued to improve during the decade ending in 1971, the life expectancy of black American males actually declined by 1.4 years - to 60.

Since 1971, however, the expected lifespan of black males has jumped substantially - to 64. But whites and black women remain far ahead in the length of time they can be expected to live, according to new figures released yesterday by the National Center for Health Statistics.

The center, part of the Development of Health, Education and Welfare, also reported that, listed among states, citizens living in the heavily black District of Columbia had the nation's shortest life expectancy, mainly because 76 per cent of the city's population is black.

The statistics testify to the continuing poorer health of American blacks and a far higher rate of violence - accidents, suicides and homicides - among blacks than among whites, officials of the statistical center explained.

In the 1960s, said Robert Armstrong, former chief of the center's mortality branch, there was a sharp drop in deaths from disease among whites and black women.But deaths from disease among black males stayed the same or went down only a little, while their deaths from violence increased substantially.

"Violent death was increasing throughout the population in the 1960s - this was the decade of riots," Armstrong said. "But violence increased most among black males and has remained high. In 1973, there were from seven to 10 times as many homicides of black males as of whites in the age groups from 15 to 29."

Why did black men fail to show greater resistance to disease in the '60s, while black female improved? No one has a complete answer, but some authorities point to the fact that black men had moved in large numbers into some of the nation's most hazardous industries and jobs, with exposure to many chemicals and environmental factors that can affect health.

The statistics released yesterday show that white men lived to an average of 67.9 years in the period from 1969 to 1971, while white women lived to an average of 75.4 years at that time. Black women averaged 68.8 years but the average black man lived only to age 60 - down from 61.4 years a decade earlier.

By 1976, however, the average length of life for black men was 64.1 years while black women averaged 73 years. White men averaged 69.7 years by 1976 while white women had the longest life expectancy - 77.3 years.

Among the states, citizens of Hawaii had the longest expected lifespans - 73.6 years - in the period from 1969 to 1971. Residents of Minnesota were next, at 72.9 years. The states whose citizens had the shortest life expectancies were South Carolina (67.9 years) and Mississippi (68 years).

District of Columbia citizenz averaged 65.7 years.

Albert P. Russo, the District of Columbia's director of human resources, yesterday called it "unrealistic" to compare the highly urban and black city with the 50 states.

But the statistic center's only index that compares Washington with other American cities - the measurement of infant mortality - also puts the District of Columbia at the bottom. Infant mortality is considered a sensitive indicator of general health.

In 1975, Washington's infant mortality was 29 per 1,000 births, while Chicago's was 24, Baltimore's 23.9, St. Louis, New Orleans and Philadelphia all hovered around 23.1.

Among nonwhites alone, only Chicago's infat mortality of 30.8 per 1,000 births exceeded Washington's 30.1. The fact that Washington is more heavily nonwhite made its overall infant mortality poorer, however.

In 1976, according to figures compiled last week, black infant mortality in Washington dropped to 27.7 per 1,000 births, and Russo said "we continue to be quite concerned" about this high rate and are "vigorously" trying to improve it.

But Russo yesterday blamed the fact that blacks die earlier than whites "primarily on unfavorable socio-economic factors."

Medical experts agree. They point to blacks' poorer nutrition, poorer housing, unhealthier neigborhoods, high joblessness and lack of equal access to good medical care as reasons for their shorter life experiences.