The Carter administration is considering a revolutionary proposal that would require doctors to accept uniform, negotiated fees rather than being allowed to set their own rates.

The proposal is contained in a draft document outlining a sweeping national health insurance plan. It was sent to the White House last week by Health, Education and Welfare Secretary Joseph A. Califano Jr. a copy was obtained by The Washington Post.

The plan, which eventually would cover every man, woman and child in the country, would begin in 1983 and be put into effect in five phases over a period of years.

Along with the proposal on doctors' fees, the first phase would set strict limits on hospital costs and provide a catastrophic illness insurance fund that would give protection for medical bills of more than $50,000.

The first phase also would expand Medicare coverage for the aged and extend Medicaid coverage to thousands of low-income prospective mothers and their children.

Future phases would include a new federal health insurance program called "HealthCare" -- to compete with private insurers' medical policies and eventually replace both Medicare and Medicaid.

The plan has not been made public, though White House aides headed by chief domestic adviser Stuart E. Eizenstat have begun didcussing it with various groups at the president's order.

The HEW document says the plan would require no net increase in total health spending, public and private, "assuming" that "tight controls" are approved by Congress.

However, many economists say health spending could rise under such a plan.

There is no estimate of additional federal budgetary cost. The plan says the federal government ultimately could relieve the states of between $3 billion and $8 billion a year in Medicaid spending, and help employers pay for catastrophic illness insurance "high-risk" employes and small groups.

As part of the effort to limit costs, Congress would set an annual spending target for all medical expenditures, public and private (currently approaching $200 billion a year, or nearly a tenth of the gross national product).

The federal government, states and private health insurers would then negotiate with hospitals and doctors to stay within the congressionally set limit, under the plan.

The plan's five complete phases would take effedt over a still undecided number of years. But in Phase II -- "probably to start a year or two after Phase I," one federal official said -- the government itself would go into the health insurance business.

Government insurance plans would be offered to employers in competition with plans sold by private insurers. Those too would be regulated to mandate broad benefits at fixed costs.

The plan includes several alternatives -- for example, whether the HEW secretary or local officials would play the chief role in physician and hospital rate-setting.

Each of the plan's phases could also be changed.

The president must also decide whether to send Congress this or a similar complete health insurance plan, or some lesser start with no hard commitment to future expansion.

Carter has repeatedly promised to propose some kind of health insurance bill this session. If he follows the HEW outline, it would look like this:

Phase I: Remove Medicare hospitalday limit. Mandate physician acceptance of set rates for the aged and poor. Mandate catastrophic illness coverage for all 25-hour-a-week or more employes, with federal-employer cost-sharing.

Phase II: Establish federal HealthCare plan for persons not covered elsewhere and some of the poor, with federal aid from general revenues.

Phase III: Mandate physician acceptance of set rates for all approved private health insurance plans.Broaden HealthCare coverage.

Phase IV: Merge Medicare and Medicaid (except for Medicaid long-term care) with HealthCare.

Phase V: Make HealthCare mandatory for anyone who lacks other coverage.