Fine-adjustment test system of hybrid integrated circuit and method of test system

The invention discloses a fine-adjustment test system of a hybrid integrated circuit. The hybrid integrated circuit is composed of a multichannel digital-to-analog converter (DAC) module, and the fine-adjustment test system comprises a signal generator, a digital dial switch, a channel selection circuit, a latching decoding unit and the multichannel DAC module. The signal generator generates first-section digital signals; the digital dial switch generates second-section digital signals; the first-section digital signals and the second-section digital signals together form input signals to be input to the multichannel DAC module; the second-section digital signals are input into the channel selection circuit to select channels of the multichannel DAC module, and selected channels are stored in the latching decoding unit; and the multichannel DAC module performs analog output on the input signals and transmits analog output results and channels to a control unit which performs feedback adjustment on to the multichannel DAC module.