Objective To investigate the correlation between body composition and nerve conduction velocity in patients with type 2 diabetes mellitus. Methods One hundred and five patients with type 2 diabetes mellitus were enrolled, body composition related parameters including body mass index, body fat percent, body muscle percent and body water percent were measured by body composition analyzer, nerve conduction velocity related parameters including motor nerve conduction velocity, distal motor latency, amplitude of compound muscle action potential, sensory nerve conduction velocity, latency and amplitude of sensory nerve action potential were determined, and the correlation between body composition and nerve conduction velocity was explored. Results Body fat percent was positively correlated with nerve conduction velocity of motor-sensory ulnar nerve and motor peroneal nerve, and negatively correlated with distal latency of sensory ulnar nerve, sensory superficial peroneal nerve, motor peroneal nerve and motor amplitude of peroneal nerve. Body muscle percent was positively correlated with distal latency of sensory ulnar nerve, sensory superficial peroneal nerve, motor peroneal nerve and motor amplitude of peroneal nerve, and negatively correlated with nerve conduction velocity of motor-sensory ulnar nerve and motor peroneal nerve. Body water percent was positively correlated with distal latency of sensory ulnar nerve and sensory superficial peroneal nerve, and negatively correlated with nerve conduction velocity of sensory ulnar nerve. Body mass index and waist circumference were negatively correlated with sensory amplitude of median nerve and motor amplitude of tibial nerve. Conclusion Body mass index, waist circumference, body fat percent, body muscle percent and body water percent may be important influencing factors of nerve conduction velocity.