Abstract: In the gold cyanidation leaching process, the immeasurability of kinetic reaction rate brings difficulties of the model identification, and estimating rate by concentration data is an ill-posed inverse problem. The noise in the measured concentration data will be amplified arbitrarily leading to unreliable results. The Tikhonov regularization method was used to estimate the kinetics reaction rate of gold and cyanide ion only using concentration, flux data and mass conservation equations without establishing any kinetics reaction model, which reduces the propagation of errors in the measured data effectively. The experimental results showed that the proposed method is easier to implement and can better track the kinetics reaction rate trends, and the method can also restrain the amplification of noise. By comparison with the methods of finite difference and smooth filter, it has better estimate performance than other common methods.