The antibacklash technology using the double motor provides a reliable solution for high precision transmission for the feed system of heavy numerical control (NC) machine tools. Aiming at solving the problem of the lack of quantitative evaluation of the antibacklash efficacy of the doublemotor system at present, a quantitative evaluation technology of antibacklash efficacy of double motor system was proposed based on improved HHT. A new signal processing and detection method based on the current changing of feed system was used to implement acquisition of detection signals with high signal to noise ratio without interference production. The EEMD and the local energy spectrum of Hilbert were used to improve traditional HHT, which was the signal processing technology for motor current, so as to solve the current information problem of non smooth stable and non Gauss distribution, to implement quantitative evaluation of antibacklash efficacy of double motor system. The simulation and experiment proves the validity of the proposed method.