The present invention discloses a circuit for improving linearity and channel compensation of PAM4 receiver analog front end, comprising a first stage and a second stage, the first stage comprising first to twentieth transistors, a first resistor, a pair of second resistors, a pair of first capacitors, and a pair of second capacitors. In the first stage circuit, the ninth and tenth transistors are directly coupled to the ground, eliminating the electrical connection to the bias current source. The Input terminals of the ninth and tenth transistors are coupled to the output signals of the preceding nineteenth and twentieth transistors, so that the ninth and tenth transistors serve as both input pairs and current source transistors. The overall current is limited by the thirteenth and fourteenth transistors, which results in a lower power supply voltage for the first stage consisting of the ninth through fourteenth transistors.