Democrats charged, and some White House aides ackowledged yesterday, that President Reagan created some "misleading impressions" in answers he gave to questions about the economy at his news conference Wednesday night.

Inaccurate statements at such conferences have dogged the president. Aides were largely satisfied with his performance Wednesday, which they felt generally avoided accuracy problems, and reported that more than 80 percent of the 412 persons who had called the White House by late yesterday morning had responded positively.

But evidence Reagan cited to counter the growing feeling that his budget cuts are hurting the poor caused Democrats to rush to their calculators and budget books and produce statements of rebuttal.

House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.), saying Reagan's defense of his program was "not only misleading but in several cases, completely inaccurate," pounced on the president's declaration that "we haven't touched Social Security."

O'Neill said, and administration aides acknowledged, that Reagan has acted to eliminate Social Security benefits for students who are children of deceased or disabled workers, to abolish aid for burial expenses and to end the minimum benefit for persons not on the rolls.

Other statements described by O'Neill and other Democrats in Congress as "misleading" included:

* Reagan's assertion that he has submitted a budget that would increase overall government spending for fiscal 1983 by $32 billion despite what he described as the "fairy tale, the myth" that his program would cause the poor and disadvantaged to be big losers under his economic program.

Critics noted, and Office of Management and Budget spokesman Edwin Dale acknowledged, that all of that proposed increase would finance Reagan's planned military buildup and that another $12.6 billion rise in federal spending is estimated for next year to make payments on the national debt. These increases are planned as Reagan is proposing cuts in a wide array of programs.

* Reagan's claim that he was not cutting a nutrition program for pregnant women, infants and small children but merging it with a health program and giving it "much greater money than it has ever had before."

Dale acknowledged that under Reagan's pending budget, total funds allocated for the merged programs would be reduced by more than $200 million next year.

* Reagan's boast that "we have in some of the hardest hit states extended the unemployment insurance" for jobless workers. In fact, budget cuts enacted last year changed eligibility formulas to reduce the number of persons receiving extended benefits.

The Labor Department estimated last fall after the changes were enacted that 1.5 million unemployed workers would lose extended benefits, but Dale said those estimates have changed since the recession. Dale acknowledged that a "quirk" in the new law caused workers in Michigan, perhaps the hardest-hit state, to lose extended benefits for a few months recently.

* Reagan's statement that his budget would allocate $2.6 billion for government-insured student loans while the last budget of the Carter administration provided only $1.4 billion.

Dale acknowledged that the increased funds will largely cover subsidies of rising interest costs and that about 200,000 fewer students would receive loans if Reagan's proposal is accepted by Congress. The decline, Dale said, would be achieved by applying a tougher standard of eligibility for the loans.

* Reagan's assertion that "more money" would be spent for vaccination programs. Dale acknowledged that funds would remain "flat" while the cost of vaccine is rising but said this would be enough to take care of all children who needed vaccinations. Congressional critics sharply disagreed.

Robert Greenstein, administrator of the Agriculture Department's Food and Nutrition Service during the Carter administration, took sharp issue with impressions that may have been left by Reagan's statement that 57 percent of food stores investigated were "selling items for food stamps that are banned."

Greenstein, who prepared a lengthy rebuttal to many of Reagan's other remarks and disseminated it to O'Neill and the press, said Reagan's remarks about food stamps may have caused the public to believe that more than half of the nation's stores are abusing the food stamp program.

He said, and current Agriculture aides confirmed, that only about 2 percent of stores redeeming food stamps are investigated and then only because of anonymous tips or because government computers indicate an unusual increase in volume of redemptions.