The invention discloses a high-precision atmospheric turbulence mismatch compensation method in a spatial chaotic laser secret communication system, and aims to solve the problems that a downlink of aconventional spatial chaotic laser communication system is influenced by a light intensity flicker effect caused by atmospheric turbulence, so that signals of a receiving end and a transmitting end are mismatched, the signal quality becomes poor, and serious error codes are caused. In order to compensate for mismatch caused by a light intensity flicker effect, improve the atmospheric interferenceresistance of a communication system and reduce the bit error rate of the system, the invention provides a method for performing mismatch compensation by taking a laser signal emitted by an existingoptical tracking and pointing subsystem in the system as a reference. According to the method, an on-board terminal does not need to be additionally launched, the number of devices needed for achieving compensation is small, the requirement for satellite miniaturization can be met, and the cost is relatively low.