In this paper, the Multisim software simulation method is used to simulate and analyze the class B complementary symmetrical amplifier circuit. Through analyzing the output waveform of the circuit load, the crossover distortion easily occurred in the power amplifier is observed. After two diodes are connected in series to the bases of the two triodes, the bias voltage is provided to set the static operating point slightly higher than the cutoff point, so that the amplifier operates in the class A and B amplification state, effectively eliminating the crossover distortion. Simulation and analysis show that Class B power amplifier is an important way to realize miniaturization, high efficiency and high power amplifier.