Viscosity-temperature relationships of eleven Chinese gum rosins were studied in the temperature range of 125℃-200℃. The viscosities were measured by means of the high temperature capillarytube viscometer, and were calculated fay the formula V =Cτ, where V (cs) is the viscosity of gum rosin; c is the constant of individual instrument, and τ(sec) is the time.The viscosity data were correlated with the softening point and the temperature in order to abtain a equation which can be used in calculating the viscosity data. The equation thus derived fits all experimental rosins with good agreement at the temperatures involved. The equation reads:where ts (℃) is the softening pOinT; t (℃) is the temperature at which the viscosity is desired; and v (cs) is the viscosity of gum rosin.With the softening point and its temperature, the viscosities of many rosins can be estimated by using the equation mentioned above,