Abstract: The specific physicochemical properties of jatropha curcas oil (especially viscosity) is an important restrictive factor that jatropha curcas oil was applied in diesel engine. Therefore, the study on physicochemical properties of jatropha curcas oil and viscosity-temperature characteristic is very important for practical application of jatropha curcas oil and has important guiding significance. The physicochemical properties of jatropha curcas oil were analyzed, and viscosity was measured at different temperatures in a variety of reagents with a rotating viscometer for studying the viscosity-temperature properties of jatropha oil. The results showed that physicochemical properties of jatropha curcas oil had some difference with that of regular diesel, but jatropha curcas oil could be a fuel of diesel engine. Moreover, with increase of temperature, the viscosity of jatropha curcas oil gradually decreased, and at 150℃, it could reach leve of diesel at room temperature (20℃), so the preheated jatropha curcas oil could be used directly as a fuel of diesel engine. In particular, the viscosity of mixed reagent (the mass fraction of 20% jatropha curcas oil and diesel fuel blends made of 80%) is more suitable for practical application.