An apparatus for recognizing a user's motions based on sensor information and label information, a method for establishing an ONMF-based basis matrix, and a method for establishing an OSSNMF-based basis matrix are provided, where the basis matrices are used to extract motion features of the user. The apparatus for recognizing the user's motions may include a feature vector extractor configured to multiply a transposed matrix of an orthogonalized basis matrix by a sensor data matrix of frequency domain sensor data acquired from sensors to extract an ONMF-based feature vector and a multi-class classifier configured to use the extracted ONMF-based feature vector to classify the user's motion into a type from among types of a user's motions.