In addition to protecting pilot’s head, flying helmet is also a mounting platform for head-mounted display, tracking and sighting systems, night vision devices, oxygen masks, and wireless communication devices. Although these helmets can greatly improve the combat effectiveness, these systems may increase the support load of head and neck, and the irrational design of helmet ergonomics will lead to the shift of Centre of Gravity (CG) of helmet and the increase of joint torque of neck, which increases the risk of neck injury to pilot. In response to this problem, this paper developed a system based on the three-point method for measuring CG of helmet, which is used to measure CG and Moment of Inertia (MI) of helmet, and to measure the physical parameters of two flying helmets. Measurement results are follows:​ mass M1 = 1.143 kg, M2 = 1.020 kg, CG C1 = (0.002, 0.542 and 7.630 cm), C2 = (0.314, 0.117 and 2.446 cm).MI J1 = (0.072, 0.089, 0.016 kg•m2), J2 = (0.041, 0.056, 0.015 kg•m2).The error analysis results show that the measurement error of system is less than 2 mm, which indicates that the system has high calculation accuracy and simple testing steps. In addition, the neck muscle fatigue test of wearing a helmet was carried out, and the fatigue degree of each muscle was analyzed quantitatively by using muscle fatigue model. This paper can provide some method support for man-machine ergonomics design of helmet, analysis of helmet mass parameter and evaluation of pilot’s neck injury.