The invention provides a human body posture identification method and system, and belongs to the technical field of security engineering. The method comprises the following steps of (1) at least collecting six parameters, including linear acceleration and angular acceleration, of a human body in X, Y and Z directions of space; (2) analyzing data features presented by the parameters, and selectingt data statistics features for each type of data as condition attributes for judging human body postures, wherein t is an integer greater than 1; (3) extracting the data statistics features of a dataset under various human body postures to form a sample set, and dividing the sample set into training samples and test samples; (4) according to the training samples and the test samples, building a decision tree classification model; and (5) based on the decision tree classification model, performing real-time classification on collected data to identify the human body postures. The human body posture identification method and system is high in identification accuracy, high in identification speed, high in adaptability to multiple input samples, and strong in robustness; and output of a classification result has high error tolerance.