On the market， there is a non-standardized phenomenon of adding mutton tallow into the beef tallow to pretend to be pure beef tallow， and there is no effective method to distinguish beef tallow and mutton tallow now. In this study， beef tallow and mutton tallow were differentiated by aroma difference. The aroma of 9 beef split tallow， 6 beef kidney tallow and 5 mutton tallow were analyzed and compared using electronic nose technology and gas chromatograph-olfactometry-mass spectrometer (GC-O-MS). The results of electronic nose combined with linear discriminant analysis(LDA) showed that beef kidney tallow， beef spilt tallow and mutton tallow could be separated into three classes. A total of 39 aroma compounds， including alcohols， esters， ketones， acids， aldehydes， and other compounds， were identified by GC-O-MS. Orthogonal partial least-squares discrimination analysis(OPLS-DA) showed that beef kidney tallow， beef spilt tallow and mutton tallow could be distinguished by their aroma. This study can provide reference for the flavor quality control and the establishment of market standard of beef tallow.