Housing and Urban Development Secretary Samuel R. Pierce yesterday responded to Patricia Roberts Harris' recent criticism of the Reagan administration's urban policy with a personal attack on her stewardship of HUD under President Carter.

In an official HUD statement, Pierce suggested that Harris, a candidate for the Democratic nomination for mayor of the District of Columbia, left HUD's finances in disarray and accused her of "willfully misinterpreting" the Reagan policy for "political effect."

Harris, who headed HUD from January 1977 to July 1979, told the Joint Economic Committee of Congress Monday that the current administration's urban policy "represents more than a federal abandonment of our cities. . . . It underscores this administration's decision to single out the disadvantaged of every age, race and part of the country to make the greatest sacrifices."

Yesterday, in a reply to Pierce's accusations's, Harris stayed on the offensive, saying: "Any statements from the administration with respect to economic matters cannot be given any credence in view of the condition of the nation's economy today as a result of Reaganomics."

A Harris campaign aide added: "It is regrettable that Pierce is making a personal attack. The real question is what is going to be best for those people."

Pierce said in the HUD statement that when he took over the department "it was almost impossible to determine how much money was owed to HUD, let alone how much of it was delinquent. When we finally straightened out the accounting mess, we found that the delinquencies did not total the reported $480 million, but rather $1.6 billion! Also, the entire HUD debt portfolio was not $10 billion as reported, but much closer to $15 billion."

Pierce's statement made no reference to Harris' successor at HUD, Moon Landrieu, who headed the department from September 1979 until the end of the Carter administration in January 1981.