Abstract: A rare species in Simocephlus-Simocephalus himalayensis,which was collected on altiplano area in Yunnan Province,China,were studied.The samples were collected both in the water area at jokul Meili (altitude,2288 meter,N 28°28′164″; E 98°47′218″) and Shangri-la (altitude,3318 meter,N 27°52′76″; E 99°39′386″) in Yunnan Province,China.The samples was reared at 15℃,20℃,25℃,30℃ and 32℃ (±1℃) respectively,and fed with Scenedesmus obliquus at density of 3×105 cell/mL.The experiment was carried out under a constant light regime of 12h.Observed four times each day,the body length was measured,the instars duration and the brood size were recorded.The result showed that the Simocephalus himalayensis which lived on the water areas of high elevation were well lived on the water areas of low elevation.Its reproduction,population parameters regarding growth,longevity and population increase were not affected by the living environment of high elevation.The main result of Simocephalus himalayensis showed below:1.Simocephalus himalayensis generally had 4 preadult instars,16-19 adult instars at 15℃,20℃and 25℃ respectively,8 adult instars at 30℃ and 32℃.The mean longevity of individuals was estimated to be 74 days at 15℃,53.5 days at 20℃,38.5 days at 25℃,24 days at 30℃ and 17.5 days at 32℃.2.The growth of body –length (L,in mm) in relation to instars (t,in instar number) could be described as:L = 1.0817Ln (t) + 0.1649(15℃) L = 1.0143Ln (t) + 0.3694(20℃) L = 0.8596Ln (t) + 0.4342 (25℃) L = 0.5929Ln (t) + 0.6899 (30℃) L = 0.6506Ln (t) + 0.4902 (32℃) 3.Temperature was a most important factor influencing the growth.In certain range of temperature,the growth speed directly proportional to the temperature,higher temperature could shorten the time for the development to maturity and life span.The relationship between the instar at maturity and water temperature of 15-32℃,for female was: y = 30250x?1.7418; The relationship curve between life span and temperature in female of S.himalayensis was: y =?4.2316x + 146.78.4.The life expectancy and specific fecundity table of S.himalayensis were given in Tab.1.The maximum average number of reproduction output per adult could reach at 449.3 at 15℃,481.5 at 20℃,446.6 at 25℃,82.4 at 30℃ and 44.1 at 32℃.The maximum intrinsic growth rate (rm) as computed from the table was 0.503/d at 25℃; the maximum net reproduction rate (R0) was 543.23 per generation at 20℃.