This paper presents a new modulation method to realize soft switching for three-phase matrix AC-DC converter (TPMC). TPMC can provide direct AC to DC transform between the grid and the DC source or loads without the traditional DC-link capacitors, thus increasing power density significantly. It is a basic requirement of TPMC to realize the soft switching, especially for MOSFETs on the AC side. The first part reviews the existing modulation methods for TPMC. Then the topology of TPMC is analyzed. Combined with current space vector modulation, a soft switching modulation method is proposed. Based on this analysis, the 3 kW, 220 V rms three-phase AC to 600 V DC prototype is built in PLECS, which verifies the feasibility of the proposed modulation method.