The invention discloses a cutting force coefficient identification method based on numerical control machine tool main shaft and servo shaft power. Through a current sensor and a voltage sensor which are arranged on a machine tool main shaft motor and a servo feed shaft motor, corresponding current and voltage data is acquired. And through further calculating, motor power is acquired. Through linear fitting, an expression function is acquired and then a cutting force coefficient of each shaft is obtained. The method is convenient and is suitable for the numerical control lathe cutting process application field. Power testing is used to replace cutting force testing. High-specification high value measurement systems, such as a dynamometer and the like, are not needed. Used measurement apparatuses mainly include the current sensor, the voltage sensor and one data collection card. A whole set of apparatus can be constructed flexibly and a price is low.