A method is proposed for the approximation and realization of the optimal transfer function of the receivers in full-response digital fiber-optic communication systems. The circuit types approaching the realization of the optimal transfer function of the receiver in low- and high-dispersion digital fiber-optic communication systems are given. A variable equalization circuit is constructed. which makes it possible to approach the realization of the optimal transfer function of the receiver in practical optical fiber links with different band- ’ widths. A practical 1.3μm and 34Mb/s receiver designed by this method and the measured results are presented. This receiver has been used in the fiber-optic communication system with a repeater spacing of 24.6km in the Institute and in the 13.4km 34Mb/s optical cable communication link in Wuhan with good results.