The utility model relates to a resonant signal simulating device for an optical pumping sensor, wherein the simulating device is formed by connecting a microcomputer with a digital system and connecting an amplification and rectification circuit with an additive synthesis circuit via the digital system and a filter circuit. The microcomputer is formed by connecting a single-chip microcomputer respectively with a TFT display, a serial port, a USB interface, an SD card and a keyboard. The digital system respectively transmits ac signals and dc signals to the filter circuit via an SPI (Serial Peripheral Interface) through frequency measurement in the modulation domain. The filter circuit is divided into a dc path and an ac path, wherein the ac path receives the ac signals sent by the SPI interface and outputs ac signals processed by a low pass filter and a signal attenuator, and the dc path receives the dc signals sent from the SPI interface and outputs dc signals processed by a resistance-capacitance filter. Resonant signals of the optical pumping sensor are simulated, so that work mechanism of the optical pumping sensor can be verified, frequency measurement in the modulation domain is realized, a resonance curve model is obtained, weakness change of optical absorption signals can be observed, work period is shortened, and the simulating device is simple and effective.