The embodiment of the invention provides a human body motion posture evaluation method and system. The method is based on the system and includes the steps that pressure induction values induced by a pressure sensor, displacement values induced by a displacement sensor and measurement values induced by an attitude measurement sensor are obtained; when the gravity center of the human body is adjusted horizontally in situ, the gravity center supporting foot of the human body is determined according to one pressure induction value; the corresponding measurement value and the corresponding displacement value are determined; the inclining condition of the upper half trunk of the human body and the displacement direction of the crotch are determined; if the inclining condition includes that the upper half trunk of the human body inclines, and/or the displacement direction of the crotch is inconsistent with the direction where the gravity center supporting foot is located, it is determined that the movement mode of the gravity center is abnormal; if the inclining condition includes that upper half trunk of the human body does not incline, and the displacement direction of the crotch is consistent with the direction where the gravity center supporting foot is located, it is determined that the movement mode of the gravity center is normal. Evaluation results are more objective and accurate, and automatic evaluation is achieved.