This experiment was conducted to investigate the seasonal fluctuation of population density of Tea red spider mite, Tetranychus kanzawai at the tea-tree plantation, and to examine some ecological characteristics under different temperatures. The results were summarized as follow : Population density of Tea red spider mite showed the highest peak in the late April, and decreased in summer season, however, increased in the early September. Under four constant temperatures of 15,20,25 and 30$^{circ}C$, the egg periods were l5.1, 8.9, 4.4 and 2.3 days, respectively. while the larval periods were 6.4, 3.5, 1.9 and 1.2 days, respectively. Developmental periods of protonymphs were 5.6, 2.8, 1.7 and 1.0 days at 15, 20, 25 and 30$^{circ}C$, respectively, while developmental periods of deutonymphs were 7.5, 4.0, 2.1 and 1.3 days. Longevity of female adults were 33.3, 16.8, 15.5 and 13.4 days and the average eggs laid by per female were 37.5, 59.4, 100.6 and 103.3 at the same temperatures, respectively. Developmental threshold and effective temperatures of each stage were 13.9$^{circ}C$ and 39.2 DD in egg stage, 12.6$^{circ}C$ and 21.4 DD in protonymphal stage, 12.6$^{circ}C$ and 18.2 DD in deutonymphal stage. The intrinsic rates of increase were 0.062, 0.134, 0.252 and 0.371 under 15. 20. 25 and 30$^{circ}C$. respectively.