The invention provides a high-precision bistatic radar time synchronization detection system and a high-precision bistatic radar time synchronization detection method. The high-precision bistatic radar time synchronization detection system comprises a transmission signal module, a reception signal module, a first frequency conversion module, a second frequency conversion module, a signal control module, a frequency standard module, a first phase-locked frequency multiplication module, a second phase-locked frequency multiplication module, a frequency synthesis module, a first synchronization detection module, a second synchronization detection module, a gate circuit module, a counter module, a signal processing module and a synchronous display module. Compared with the conventional time synchronization detection technology, the high-precision bistatic radar time synchronization detection method regards a phase coincidence point, namely, a time synchronization point as gate opening andclosing signals of the gate circuit, and eliminates the counting errors with +/-one character in the conventional time synchronization detection; and the high-precision bistatic radar time synchronization detection method further adopts a different frequency phase synchronization detection principle which is different from the conventional phase detection method, so that the measurement precisionis greatly increased, the measurement system has higher stability in a complicated background, and the safety and reliability are higher.