The invention discloses an improved generation method of a multiphase filter, and belongs to the field of radio techniques. The method comprises the following steps of according to operation requirement parameters, generating an FIR filter based on a window function method of the FIR filter; dividing the FIR filter into n first sub-filters, to form n multiphase filter banks, wherein n is more than and equal to 2; further dividing the FIR filter into n second sub-filters, using second sub-filters of which the passband is adjusted as baseband filters, and adding the baseband filter between each two adjacent first sub-filters, wherein the passband of the added baseband filter is within the stop band of the two first sub-filters connected therewith. The method is applied to the multiphase filter, and can effectively eliminate spectral interference between the filter banks.