The invention discloses a linear trans-conductance converting circuit system. The linear trans-conductance converting circuit system comprises a linear trans-conductance converting circuit, wherein the linear trans-conductance converting circuit comprises a voltage input end and a circuit output end; the linear trans-conductance converting circuit is used for converting the input voltage linearity into the output current. In the system disclosed by the embodiment of the invention, the voltage signal is respectively input into a source electrode of the N-field effect tube and the grid electrode of the P-field effect tube, and the same setting is performed on the trans-conductance parameters of the N-field effect tube and the P-field effect tube, the difference of the threshold value voltages of the N-field effect tube and the P-field effect tube is utilized so as to subtract the currents on the N-field effect tube and the P-field effect tube, wherein the obtained output current and the input voltage are in linear relation. The existing system adopts the CMOS process, but the voltage and the current of the field effect tube are in a square relation in the CMOS process, so that the CMOS process can be directly used for the linear trans-conductance; the method used by the invention well solves this problem.