Abstract: A calibration curve method using pure oil (soybean oil or rapeseed oil) was proposed to determine the oil content of soybean and rapeseed seeds in NMR. The accuracy,repeatability and recovery of the determined result were also evaluated and compared with Soxhlet determination. The result showed that the calibration curve generated when ATT as 22 db and the weight of pure oil as 0.600 0～0.720 0 g may be used to determine the oil contents of soybean seed, accordingly, when ATT as 31 db and the weight of pure oil as 1.300 0～2.200 0 g may be used to determine the oil contents of rapeseed seed. There were no significant differences in oil content of seed between this method and Soxhlet method, the coefficient of correlation were above 0.956 6. The method was proved to be accurate, reliable and easy to operate.