Abstract : Global climate change poses severe challenges to rice production in China, and the identification and evaluation of major agronomic traits of rice varieties under high and low altitude environments are of great significance for breeding cold-tolerant and climate-adapted rice varieties. Using 436 rice varieties of diverse geographical origins from China and abroad as experimental materials, this study conducted a two year repeated and precise identification of major agronomic traits at the high altitude identification site in Songming, Yunnan and the low altitude identification site in Caofeidian, Hebei. The results showed that the major agronomic traits of rice varieties exhibited significant differences between high altitude and low altitude environments; the phenotypic mean of plant height, panicle length, effective panicles per plant and seed setting rate at the low altitude site in Caofeidian were significantly higher than those at the high altitude site in Songming, while the heading stage was delayed, the days to heading were increased, and the grains per panicle increased accordingly at the Songming site. There were significant differences in low temperature response index (LRI) of seed setting rate among rice varieties from different origins. Among them, varieties from Yunnan and Japan varieties had the highest LRI of seed setting rate, exhibiting strong cold tolerance. Based on the division of rice growing region in China, the rice varieties from the southwest and northwest rice growing regions had the highest mean LRI of seed setting rate and thus strongest cold tolerance, followed by those from the north China and northest rice growing regions.Under high and low altitude environments, the stability coefficients of panicle length and effective panicles per plant were relatively small, with stable phenotypic values and low susceptibility to environmental variations; the days to heading had the largest stability coefficient, corresponding to the poorest phenotypic stability and the highest sensitivity to environmental changes. Cluster analysis showed that the genetic relationship of rice varieties from different origins was somewhat correlated with the geographical location and latitude of their provenance, and rice varieties with similar geographical locations or latitudes exhibited closer genetic relationships. This study also screened 20 accessions of cold tolerant rice varieties, such as Koshihikari, Maihime, Hitachi 23 and 20 accessions with good stability of days to heading under high and low altitude environments, such as Sujing 2, Zhongzuo 58, Hongqi 5. These materials can serve as excellent parents for use in breeding programs targeting cold tolerance and climate change adaptability in rice.