The common mode voltage (CMV) and the reactive current compensation are two important problems for the transformer-less current source converter (CSC). A modified space vector modulation method is proposed to suppress common mode voltage and at the same time, actively control the reactive power flow for power factor correction. The relationship associated with the common mode voltage and space vector modulation was analyzed in detail. Then, an improved space vector modulation method with choosing zero vectors is proposed. To compensate reactive current of system, reactive power control strategy is developed through the dq-axis coordinate transformation.