Cash in Bank ATM belongs to Interest free funds, to ensure there is sufficient cash in ATM for people to extract, at the same time, waste of resources that we do not wish to see. Daily ATM cash surplus in the less is better. Combined Matlbe programming techniques to optimize smoothing parameter α of cubic exponential smoothing forecast model, compared with the relevant literature, without human trials, it will soon be able to determine the optimal α values, thereby establishing the optimal parameters of three exponential smoothing forecasting model. Bank ATM cash flows were forecast by three exponential smoothing, and calculated by Matlab. The results showed that the prediction error was minimal, and it can well play a guiding role on how much cash input the ATM a day.