The District of Columbia could receive an additional $50 million annually in welfare, economic development, employment and housing assistance under the national urban policy program announced by President Carter, according to an analysis released last week by the D.C. Office of Budget and Management Systems.

The analysis noted that the urban aid program still could undergo many changes as it moves through Congress.

If carried out as envisioned by the Carter administration, the program could provide the city millions in fiscal relief, city Budget Director Comer S. Coppie said.

The analysis said that the major benefit to the city probably would be in welfare reform. The federal share of welfare costs, now 50 percent, could increase to 90 percent, providing an additional $30 million to $40 million annual reimbursement to the city. Carter's welfare proposal, however, probably will not pass this Congress, the report noted.

The city could receive another $1 million for its low-interest rehabilitation loan program and the Carter plan would expand the program's eligibility to owners of multi-family units. In addition, the grant program for urban parks could yield the city $3 million over a three-year period, the analysis said.

Under proposed economic and urban development programs, the city also could receive significant assistance.

The city already has applied for $10 million to $15 million in grants under these programs, but it is uncertain how much the city will receive or how much its share would increase with the proposed additional funding.

Under the planned "soft public works" program that would create jobs for the long-term unemployed through renovation of public facilities, the city could receive an additional $7 million to $8 million a year for three years, generating several hundred jobs, the analysis said.

In addition, social service programs such as day care centers may be expanded. Supplementary revenue sharing funds would be replaced with a new fiscal assistance program that probably would sustain funding at current levels, the analysis said. The city has received about $17 million over a 27-month period from that source.

Carter unveiled his $8.3 billion urban aid plan March 27. The plan is designed to help financially troubled central cities by promoting rational growth and fiscal health in urban areas. A large part of the plan consists of more than 150 proposed changes in programs already in existence.

Mayor Walter Washington said last week that he is "pleased by the new thrust because it could provide us with much greater flexibility. I am hopeful that it will enable us to use a combination of programs to meet our greatest needs such as increasing employment opportunities and stimulating investments in the District."

The analysis said other parts of Carter's plan could be "possibly significant" to the city. Those include an urban volunteer corps that could provide funds for Advisory Neighborhood Commissions, a community development credit union program that could fund at least one city neighborhood organization and a "liveable cities" plan that would support community-based arts programs.