A method, a system and a terminal for identity authentication, and a computer readable storage medium are provided. The method includes: acquiring a human body image of a person to be authenticated, and determining from the human body image a plurality of skeleton key points of the person to be authenticated; converting the skeleton key points into feature data, and combining the feature data to form physique feature information characterizing the person to be authenticated; processing the physique feature information using a physique feature model by inputting the physique feature information into the physique feature model, to obtain a processing result; and recognizing the identity of the person to be authenticated based on the processing result of the physique feature model.