A new computing method of transmitted efficiency about clutch actuation system was put forward through the analysis on the structure of clutch actuation system and influence factors of transmitted efficiency. Combining with the test bed of clutch actuation characteristic, the test program was established. The transmitted efficiency about clutch actuation system was respectively tested under two working conditions with constant speed and variable pedal speed and with variable speed and constant pedal speed during two processes of pressing and releasing pedal. Results indicate that the transmitted efficiency of clutch actuation system on the basis of the test program and the computing method has a good repeatability. And during pressing pedal process, the force and stroke transmitted efficiency are increased with pedal speed rising. During releasing pedal process, the force efficiency is decreased and the stroke efficiency is increased with pedal speed rising. The variation of speed makes no difference to the force and stroke transmitted efficiency below 2 000 r/min.