The corrosive behaviors of T2 pure copper in different biodiesels such as rapeseed oil, corn oil and soybean oil and 0# diesel were studied by soaking method at ambient temperature. The corrosion rate, percentage of C and O, surface precipitates and electrochemical stability of samples were studied after soaking of 672 h. The results show that the corrosion rate of T2 pure copper in three kinds of biodiesels is higher than that of diesel fuel. The carbonyl group in fatty acid methyl ester in biodiesel is the main cause for the increase of precipitates on metal surface. The corrosivity of the three kinds of biodiesels to T2 pure copper was rapeseed oil, corn oil and soybean oil in ascending order. The difference of carbon chain length and saturation in fatty acid methyl esters in different biodiesels may be the root cause for corrosion strength difference.