The District of Columbia, barred by Congress from imposing an income tax on commuters, continues to generate far more income than it is able to tax, according to a new city report.

The report, based on figures for 1979--the latest available--shows that in that year, 45 percent of the metropolitan area's total income was earned in the city. But only 17 percent of the total was earned by city residents, and thus was within the reach of the city's income tax.

The report also showed that in 1979, only 8.3 percent of the nearly 500,000 persons in the area who earn more than $20,000 lived in the city.

"It is evident that the District must seek a solution to the uneven distribution of income in the Washington metropolitan area if it desires to maintain a viable income tax base," the report concluded.

However, city officials said yesterday there is little hope that Congress would allow the city to tax commuters. In the past, proposals for a commuter tax have encountered stiff opposition, particularly from congressmen representing the Maryland and Virginia suburbs.

"That comes up year after year, and the District has been rebuffed," said Roger Powell of the city's Department of Finance and Revenue. Most states, including Maryland and Virginia, and 4,450 cities have some kind of commuter tax, according to city officials.

Based on the city's current income tax rates, Powell said yesterday, the city could collect about $416 million if it taxed the incomes of nonresidents.

According to the report, D.C. residents reported 1979 gross incomes of $4.4 billion, an increase of 8.7 percent over 1978. The average income in the District for 1979 was $13,909, compared to $19,242 in Maryland and $21,298 in Virginia.

A total of $25.5 billion was earned in the metropolitan area, up from $23.1 billion the year before. While 45 percent of that sum was earned in Washington, 28 percent was earned in Virginia and 27 percent in Maryland.

Single persons accounted for 164,235 of the tax returns in Washington, compared to 105,406 by married persons. D.C. taxpayers claimed a total of $632,270,788 in deductions.