The invention relates to a time-frequency synchronization method of a networked radar system, and relates to the technical field of networking radars. The networked radar system defines a fusion control center as a main station which is used as a reference standard of the whole system, and defines other radar stations as secondary stations, wherein the main station and the secondary stations can receive satellite time service, time-frequency comparison information is added on the basis of information, such as detection information, control information, state information and other information,transmitted by an original data communication channel between the main station and each secondary station, bidirectional time-frequency comparison is performed between the main station and the secondary stations, a time difference between the main station and the secondary stations is calculated, and a local frequency source is corrected by utilization of clock difference information, so as to achieve time-frequency synchronization of the networked radar system. The time-frequency synchronization method of the invention solves the problem of time-frequency synchronization of the networked radar and improves the accuracy of a final output time-frequency.