In order to reduce line-side current harmonic caused by switching frequency and achieve electrical isolation, a grid-connected inverter with a T filter and an isolation transformer is used. To make up for the shortcomings of independent PI control of current and low response rate of traditional current-SPWM control, the method of current- SPWM control of tracking current momentary value with PI control of current and voltage feed-forward is presented. With the analysis of control principle of grid-connected inverter, control model of the grid-connected inverter is designed, transfer functions of every control link are derived and PI parameters are designed. At last, the Matlab simulation results show that the control strategy is feasible.