Abstract: The preparation and properties of biodiesel from rapeseed oil containing high content of erucic acids were systematically investigated in this paper. The composition of obtained biodiesel was analyzed with gas chromatographymass spectrometry (GCMS). The results showed that the components of the resulting biodiesel were the methyl esters of erucic acid, oleic acid, linoleic acid and eicosenoic acid. The main factors affecting the transesterification of rapeseed iol, such as molar ratio of methanol to oil, reaction temperature and catalyst (potassium hydroxide) dosage, were also discussed. The suitable conditions for biodiesel preparation were molar ratio of methanol to oil 5∶1, reaction temperature 60℃ and catalyst dosage 1％. Under the conditions the yield of fatty acid methyl ester was 923％.The properties of the biodiesel such as cetane value, caloric value, acid value, viscosity and flash point were tested according to the standard methods. It was indicated that the biodiesel could meet the requirements as fuel, even prepared from rapeseed oil containing high content of erucic acids.