President Reagan yesterday rescinded a four-year-old executive order that required agencies to prepare reports on the impact of new federal budget proposals, programs and regulations on urban areas.

President Carter had instituted the "urban impact statements" as part of his program to shore up declining urban areas. The statements were required so that the administration could make sure agency decisions were in line with its own urban policy.

The impact statements were targeted by the Presidential Task Force on Regulatory Relief a year ago, as part of its drive to reduce what it considers unnecessary and burdensome federal regulations.

The White House noted in its announcement yesterday that the General Accounting Office concluded last July that the program has been "only minimally effective."

A review by the Office of Management and Budget found that 47 analyses "prepared by 15 different agencies over the past three years had contributed little additional information for decisions," the White House said. "Substantial improvements needed to make it work would duplicate existing budget processes."

The White House said the impact statements were redundant now that Reagan has established a full-scale regulatory and paper-work review process.

Finally, the White House said, "The administration's enterprise zone proposal, with emphasis on deregulation and private participation, is a much more effective means of dealing with urban issues." The plan would provide tax incentives to encourage employers to locate in depressed urban areas.