This paper attempts to apply the ARMA (Auto Regressive Moving Average) model to predict patients' glucose concentration because of the successful application of time series ARMA model in forecasting the fault rate. This paper gives the glucose concentration prediction method based on ARMA model and the actualization on MATLAB platform. After analyzing the time series of several patients' glucose concentration, use MATLAB platform to calculate the parameters of ARMA model, then predict the glucose concentration. The prediction process and results show that the ARMA model is suitable for some patients' glucose concentration.