In the surgery of lumbar disc herniation ( LDH ) , the nerve root retractor is used to pull the nerve root to prevent damage. The traditional medical nerve root retractor cannot quantify the force on the nerve root. In order to improve the nerve root retractor, this paper proposes an intraoperative lumbar neurological force monitoring system. The core module of this system is the improved nerve root retractor equipped with the high density flexible pressure sensor array. The high density micronee-dle array and multiple pressure detection units are used in the pressure sensor to realise sensitive pressure monitoring in a narrow surgical operation area. The sensing area is 4 mm × 17 mm, inclu-ding 6 detection units. The sensitivity of sensor is 67. 30％/N in the range of 0-5 N. This system is used for in vitro animal experiments, which can continuously detect pressure.