It is important to improve the overall quality of rice grown in northeastern China, which is famous for its high yield. Therefore, it is necessary to study the quality of japonica rice resources in the region. This study analyzed 71 rice samples from the Liaoning, Heilongjiang, and Jilin Provinces, focusing on grain shape, endosperm composition, and taste. Significant regional differences were observed in taste and edibility, with the samples from Heilongjiang and Jilin generally scoring higher taste value, which was significantly higher than the Liaoning variety. However, the Liaoning varieties were more stable in terms of the sensory evaluation of taste. Obvious differences in grain length were detected among the samples, with the varieties from Jilin and Heilongjiang Provinces predominantly having short and medium-to-long grains, respectively, and those from Liaoning Province having diverse grain shapes. However, there was no correlation between grain shape and taste. This indicated that the taste of rice is not affected solely by its external morphology but also by multiple interacting factors. There were significant differences in endosperm composition among the three provinces, but the amylose content of the tested varieties was generally less than 18%, and the protein content was about 6%. Additionally, the Jilin Province varieties had the lowest apparent amylose content and long chain of amylopectin (Fb3), the Heilongjiang Province varieties had the lowest protein content, and there were more medium chains of amylopectin. Notably, protein content was negatively correlated with taste but positively correlated with pasting properties. It can be seen that the premise of varieties in different provinces showing good taste characteristics is to ensure the content of amylose and protein is low, and adjust the proportion of amylopectin chain length. [ABSTRACT FROM AUTHOR]