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Understanding the sequence diversity of rice blast resistance genes is important for breeding new resistant rice cultivars against the rice blast fungus Magnaporthe oryzae.In this study, we selected 24 rice cultivars with different genetic backgrounds to study the allelic diversity of rice blast resistance genes Piz-t, Pitaand Pik.For Piz-t, a total of 17 allelic types were found within the 24 cultivars. Blast inoculations showed that most of the mutations can affect the function of the resistance gene. For Pita, except for the difference at the 918th amino acid, a majority of the 21 mutations were detected among the cultivars. Inoculations with blast isolates carrying Avr-Pitarevealed that cultivars with mutations in other sites except for the 918th amino acid did not affect the function of the Pitagene. For Pik, a total of six allelic types were found within the 24 cultivars, but five of them lost the function of the resistance gene. In addition, we found that Piz-t, Pita and Pikwere expressed constitutively in the 24 rice cultivars and the expression level was not related to resistance. Our results have provided the sequence diversity information of the resistance genes Piz-t, Pita and Pikamong the popular rice cultivars grown in the northeast region of China.