In the process of rocket flight test, the engine turbo pump speed is generally calculated by continuously processing the pulse period output by the measuring equipment. Restricted by relay tracking and receiving conditions, telemetry data are discontinuous, and always encounter short-time interruption and other phenomena, which can easily cause data processing errors. By studying the state and state transmission, and analyzing the data interruption and abnormal disposal during real-time tracking, a processing model based on finite automaton theory is proposed, which effectively solves the continuous judgment of measurement data.