The utility model discloses a switch quantity signal conversion device which comprises a switch quantity signal conversion and control module which receives at least one switch quantity input signal, converts the switch quantity input signal into an electric signal of a switch, and drives the connection and disconnection of a first photoelectric isolation coupler according to the electric signal of the switch; and the first photoelectric isolation coupler which isolates a drive switch quantity signal output module and enables a switch quantity output module to output an in-phase switch quantity output signal and an inverted switch quantity output signal corresponding to the switch quantity input signal. Through the device disclosed by the utility model, since an optical isolation relay with the advantages of rapid switching speed and no jitter of switch signal output is used, the synchronous response of a switch quantity input signal and a switch quantity output signal can be realized, a time delay is small between each other, the response is rapid, and a requirement of digital real-time simulation is achieved.