Twenty four single crystals of molybdenum of different orientations after extension at -80℃ (-50℃), 27℃, 1000℃ and ～2000℃ were investigated. From a study of metallographic and X-ray diffraction results, it was found that the slip traces, {112}, {123}, {145} etc., may be interpretted as conjugate slip in two nonparallel {110} planes along the same direction. The appearance of slip traces was different for different orientations of specimen. At different temperatures of extension, the appearance of slip traces of the same specimen orientation may be the same or different depending on the specimen orientation.