This paper gives a new method which determines the content of zinc chloride in activator solution for producing activated carbon by indirect iodometry method after prcdccolor and removing iron (Fc3+and Fe2+) .This method has a sharp point and higher precision and accuracy. It has less interference and simple procedure. Experiments shocd that the relative standard deviation of this method was about 0.5% and relative error was less than 1%. The new determination method can improve the quantity problem of product from controlling the content of zinc chloride in activator solution by determining Baume degress method.