According to the charging demand of modern tram and charging characteristics of supercapacitor,the charging method of constant current first and constant voltage second is used in this paper.It is proposed that the AC/DC side of charging device uses PWM rectification technology,and the DC/DC side adopts the control strategy of giving the initial value to integrator.The implementation scheme is analyzed in details,simulation model is built to verify the control strategy,the simulation results and experimental results show that this control-strategy greatly reduces the influence of the charging device on the power grid,the peak value of the output voltage and output current at the moment of conversion between the charging methods is very small,which have a positive impact to promote the promotion of modern tram in the major cities.