The invention relates to a method for a robot to identify a user identity. The method for identifying the identity of the user by the robot comprises the following steps of: obtaining a face image ofthe user by using a camera; segmenting the face image by adopting a binary segmentation method; carrying out image enhancement on the segmented face image; obtaining gray feature points in the face image; comparing the acquired gray scale feature points with preset gray scale feature points; if the obtained gray scale feature points are inconsistent with the preset gray scale feature points, sending a user identity recognition failure prompt; if the obtained gray scale feature points are consistent with the preset gray scale feature points, putting the palm of the user on an impedance acquisition device, wherein the impedance acquisition device acquires the impedance characteristic when the excitation current with the preset frequency flows through the palm cells of the user, and if the impedance characteristic is consistent with the preset impedance characteristic, judging the identity of the user corresponding to the impedance characteristic.