Evaluation of the protein content is a major indicator of the nutritional quality of rice, and the protein quality of rice is the best among cereal crops. Essential amino acids play an irreplaceable role in human growth, development and health care. Essential amino acid is a key ingredient to measure the nutritional value of rice. Using the experimental rice processed from the rice variety "Yuzhenxiang" sprayed with plant nutrients (patent number: ZL201110103910.9), namely high essential amino acid nutritional rice, combined with five kinds of high quality rice imported by COFCO and homegrown "Wuchang rice", we send the samples of the seven kinds of rice to Hunan Food Testing Center, and adopt HPLC method to test the content of protein and eight kinds of essential amino acids. Three bags of rice are randomly selected for each kind of rice, and each bag is a replication. The test results show that there are highly significant differences in the content of essential amino acids between different kinds of rice (F=246.29**, P=5×10-71), and there are also highly significant differences in the content between different kinds of essential amino acids (F=3937.09**, P=4×10-146). The test results of protein content indicate that there are highly significant differences in the content of protein between different kinds of rice (F=3937.0973.29**, P=5.81×10-11), and the test results of lysine content show that there are highly significant differences in the content of lysine between different kinds of rice (F=3937.0973.29**，P=5.81×10-11).