Abstract: For image defects such as partial color, trailing and double caused by complex circuit, amplification imbalance of primary colors signal and signal wave reflection of VGA distributor, a multiplex distribution circuit of VGA signal was designed based on analysis of transmission characteristic curve of voltage of CMOS inverter. The circuit uses CMOS inverter as amplifier circuit of small simulation signal, adopts 74HCU04AP integrated circuit to design R, G, B three primary colors amplifier circuit, and uses emitter following circuit to drive output signal, which can provide outputs with 75 Ω load more than 4 channels, and realize function of 1 input of VGA signal and multi-output of VGA signal. The practice proved the circuit has simple structure, low cost and high reliability.