Rep. Al Ullman (D-Ore.), yesterday unveiled a proposal chairman of the House Ways and Means Committee, for a modest reduction in the present "double taxation" of corporate income and stockholder dividends - a provision he hopes to add to President Carter's tax-cut package.

Ullman's plan, to be outlined in more detail in this morning's Congressional Record, would allow stockholders a tax credit amounting to 10 percent of the dividends they receive. The credit would be claimed at the end of each year based on a form sent out by the company.

The chairman's proposal was similar to in structure - but only half as big as - a measure considered by Carter last autumn. The president was planning then to propose a 20 per cent credit for stockholders, but later scrapped the plan as too complicated and costly.

Ullman said earlier this week that despite the president's decision to abandon the program, he thought it was important to include the provision in the tax bill now being considered by the Ways and Means Committee. He described the 10 percent credit as "a foot in the door."

It was not immediately clear whether the Carter administration would support Ullman's action. Treasury Secretary W. Michael Blumenthal told the Ways and Means chairman earlier this week the White House position would depend on the overall cost of the tax bill.

The Treasury's original proposal would have cost an estimated $4.1 billion in lost revenues for a credit twice the size of the one Oilman proposed. Ullman provided no cost estimate in his package yesterday, but aides suggested his plan might run less than half what Treasury's cost.

Ullman's plan is less generous than Treasury's in one respect: It would not allow stockholders to share in their credits on the actual tax the corportion paid. The Carter proposal would have counted the investment tax credit as a tax paid by the corporation.

As a result, corporations which pay only small amounts in taxes would have less in tax credits to "pass out" to their shareholders. Some corporations with particularly large incomes from foreign sources have argued that such a formula would place them at a disadvantage.

Ullman described his proposal as only a start. The 40 percent credit would be increased gradually, by 2 percent a year, to a maximum of 20 percent by 1964. The present $100 dividend exclusion allowed all, taxpayers would not be affected.

The theory behind Ullman's proposal is that it is unfair to tax corporate income twice, first as profits and later as stockholder dividends. The chairman's plan would reduce this "double taxation" by relieving the shareholder of the second tax burden.

Under Ullman's proposal, the corporation would continue to pay taxes on the money it distributes as dividends, except that it would "withhold" 10 percent from dividend checks, much as now is done in the case of employee paychecks.

At the end of the year, the company would send stockholders a form telling them the dollar amount of the credit to which they're entitled. Shareholders then would claim the credit to reduce the amount of taxes they otherwise would owe.

For example, if a stockholder in the 40 per cent tax bracket receives $100 in corporate dividends, under existing law, he would owe $40 in taxes. But under Ullman's proposal, he would pay $34-$44 on 110 per cent of the $100 dividend, minus a $10 credit.

The procedure for calculating the tax credit, known to accountants as "grossing up," would provide a smaller tax saving for higher-income taxpayers. As a result, Ullman contended, the bulk of the benefits would go to lower-income stockholders.

Although Ullman - and some committee members - support the credit proposal, the measure has been criticized both as too complex and skewed toward the rich. A similar system is in operation in Britian.

The administration had included its earlier proposal in preliminary drafts of the tax package in part as a form of compensation for a companion plan to end the special tax treatment of capital gains - profits from the sale of stocks or other property. However, that measure has been scrapped.