The invention discloses a lubricating oil viscosity detecting device. The device comprises a placing mechanism, an adjusting mechanism and a detection mechanism. The adjusting mechanism is installed at one end of a top of the placing mechanism, and the detection mechanism is fixedly installed on one side of the adjusting mechanism. The placing mechanism consists of a supporting bottom plate, a supporting leg, a buffer groove, a buffer supporting plate, a buffer spring, a buffer rod, a damping groove, a damping spring, a fixing block, a unloading force slide rod, an unloading force spring, a pushing slide block, a transmission rod, a connection block, a rubber pad, a material barrel, a semiconductor refrigeration sheet and an electric heating plate. A multi-layer damping buffer mechanism isarranged in the placing mechanism, and an impact force generated by concussion is offset through the damping mechanism so as to prevent the concussion from affecting detection. Through setting the semiconductor refrigeration sheet and the electric heating plate, lubricating oil viscosity can be conveniently detected under different temperature environments, and through a pressure sensor and a viscometer, the lubricating oil viscosity can be detected from multi-azimuth angles. A detection result is accurate and effective.