The utility model discloses a high-speed isolation communication circuit based on a low-speed optical coupler. The circuit comprises a low-speed optocoupler, a triode, a pull-up resistor and a pull-down resistor, the low-speed optocoupler comprises a light emitting diode and a phototriode; a collector electrode of the phototriode is connected with a power supply Vcc '; wherein the emitter electrode of the phototriode is directly connected with the base electrode of the triode, the emitter electrode of the triode is directly connected with the ground, the pull-up resistor is connected between the collector electrode of the triode and a power supply Vcc ', and the pull-down resistor is connected between the base electrode of the triode and the ground. Compared with the prior art, the low-speed optocoupler utilizes the current-limiting resistor and the pull-up and pull-down resistor to adjust the on-off delay of the phototriode and the external triode in the optocoupler, significantly improves the performance of the low-speed optocoupler when the low-speed optocoupler is applied to high-speed signal isolation transmission on the premise of ensuring low cost, and expands the application of the low-speed optocoupler.