Auto Regressive model (AR) of nanoTiN particles content in Ni-TiN composite coating was established by the method of Time Series Analysis. The trend of the nanoTiN particles content variation was forecasted with the AR model,and the prediction value and experimental test results were compared. The results show the model may forecast the nanoTiN particles content in Ni-TiN composite coating. And the average deviation is about 5.2884%. The average grain size for Ni and TiN is approximately 52.85 and 39.13 nm, respectively.