Abstract: To improve the integration and dynamic range of the front-end readout electronics of the Multi-Wire Drift Chamber(MWDC) in the track detector for the external target experiment at HIRFL-CSR, a 32-channel on-board front-end circuit based on the ASD chip was designed to verify the feasibility of the ASD(Amplifier Shaper Discriminator) + HPTDC(High-Performance TDC) readout scheme as a replacement for SFE16 + HPTDC. The circuit primarily consists of a protection circuit, time conversion circuit, and differential driver circuit. Electronic performance tests have been completed under laboratory conditions, including the time accuracy test across the dynamic range, the time accuracy test at two threshold values, and the leading-edge jitter performance test. Test results demonstrate that the 32-channel front-end circuit achieves a dynamic range of 1 200 fC, with a leading-edge jitter time resolution better than 80 ps. Moreover, under a threshold of 0.3 V and a dynamic range of 100 to 1 200 fC, the sigma of TOT jitter is better than 150 ps.