The U.S. Court of Claims last week upheld the constitutionally of the so-called "marriage penalty" in the federal income tax system - the disparity that often forces married persons to pay higher taxes as a couple than they would if they were single.

In a unanimous decision, the court rejected a challenge filed by a Falls Church couple seeking a $1,220.00 refund for what both partners had claimed was overtaxation resulting from the marriage penalty disparity.

The ruling marked the second time this year the marriage penalty has been upheld as constitutional. In January, the U.S. Supreme Court turned down a suit that would have challenged the disparity as discriminatory. The decision can me appealed.

The disparity caused by the marriage penalty has stirred increasing protest in recent years as a greater proportion of the nation's married women began to hold full-time jobs.

However, policymakers have insisted they are unable to eliminate the problem. The Carter administration considered proposing a special tax break to deal with the problem in a "tax reform" bill it was drafting last September, but later scrapped the idea.

The disparity came into the tax law in 1971 as part of a restructuring of the tax code to ease the penalty that existed then against single persons. At present, couples pay up to $180 more in taxes a year than they would if the two partners were single.

The Court of Claims concluded yesterday that "tax disparities will exist no matter how the rates are structured" and that the courts "are neither equipped nor inclined to second-guess the legislature" in deciding tax policy.

Paul Mapes and Jane Bryson filed the suit. They contended they would have had to pay only $7,312 if they had been single persons, but would up having to send the Internal Revenue Service $8,532.10 filing jointly as married persons.