Some researches of the fishery regionalization in China are of certainpractical significance for reasonably utilizing the natural condition. Up to now, ne-vertheless, these analysis of division about the climatic condition were only somescattered datum of air-climate,but a systematic elaboration on the hydro-climate forliving fish directly is in lack. This paper based on 24 groups of relation between thehydrotemperature and the airtemperature ,a equation that it may calculate the hydro-temperature in different regions are proposed. This equation includes three factors--airtemperature, latitude and altitude. The hydrotemperature (T_A) is given by TW=[a+b(N-a)+cH]T_A+[d+e(N-a)+fH]where TA-airtemperature; N-latitude; H-altitude;α-parameter of latitude; these let-ters of a, b, c, d, e and f are different equation's parameters. Based on the diagramof some linear relations between the hydrotemperature and the airtemperature, twotypes of climatic equation are distinguished. One of them is the continuous changetype for month average of hydrotemperature in a year, and another is the unconti-nuous change type. Using each airtemperature datum we have estimated the hydretemperature ofrivers at 530 locations in the eastern China. After that, on the ground of the biolo-gical boundary temperatures of freshwater fishes with various therm-ecotypes, anorthern limit for warm-water fishes over winter safely and a southern limit forcold-water fishes over summer safely are determined respectively. The limit of for- mer is defined to connect with Wenzhou, Chenzhou and Bijiang, but the latter isdrawn a line from Cangzhou, Shijiazhuang, Xinxiang, Yuncheng, Shangxian,Hanzhong, Ya'an up to Xichang. In addition, 4 esotherms of cumulative hy-drotemperature which take 10℃ and 15℃ as the biological criterias are given,itdivide the eastern China into 5 climately adaptative regions for the growth offreshwater fishes. Each climatic region have the different value for to cultivativefishery. The climatic adaptability of fishes for growth can defined by the divisionof cumulative hydrotemperature. Among them, these temperate-water fishes ofChina grow quickly and may give some better benefits in the south of the esothermof ΣT₍₁₅₎≥4700 degree-day.