Abstract: In order to explore the influence of different seasons on the expression of distinctness, uniformity and stability of Oryza sativa L. and provide practical experience and theoretical support for the DUS testing in Hainan, in this paper, according to the testing theory and technology of distinctness, uniformity and stability of Oryza sativa L., based on 4 growing cycles of the 4 rice materials, the influence of different seasons on the expression of related characteristics were analyzed. The results indicated that, during the 4 independendt test cycle, excluding the awn, the observations of quality characteristics were consistent. The expression of 14 pseudo-qualitative characteristics was not effect the conclusion of assessment of DUS. The difference of 10 qualitative characteristics in the analysis of variance was obvious, but the application varieties and similar varieties were consistent. The conclusion of assessment of DUS was not changed. There was no obvious difference of the expression of other 17 qualitative characteristics which were visual assessment. Therefore, there was no obvious difference of assessment of DUS during different seasons for DUS testing of rice in Hainan. Considering the multiple places and multiple seasons for the DUS testing was useful for tropical area to accelerate the development of rice variaty protection.