A Doppler parameter quadratic fitting method based on time division multiplexing comprises the steps of (101) establishing a quadratic fitting unit which comprise a multiplying unit a2, a multiplying unit b2, a multiplying unit c2, a multiplying unit d2, a multiplying unit e2, a divider a2, a summator a2, a mean value module a2, a mean value module b2 and a mean value module c2; (102) calculating fitting parameters m, m21, m22, m23, m24 and m25 by means of the quadratic fitting unit with the abscissa xi of a scatter signal as the input end; (103) calculating the fitting coefficient summation by means of the quadratic fitting unit based on the fitting parameters m, m21, m22, m23, m24 and m25; (104) achieving quadratic curve fitting of the scatter signal based on the fitting coefficient summation. Compared with traditional quadratic fitting, the Doppler parameter quadratic fitting method based on time division multiplexing has the advantage that the number of hardware resources needed is reduced greatly by means of time division multiplexing of hardware resources in the quadratic fitting unit.