The invention relates to a power module manufacturing method for connecting nano-silver soldering paste with bare DBC (Direct Bonding Copper). The method comprises a cleaning process, a soldering paste printing process, a chip mounting process and a sintering process. In the cleaning process, the bare DBC is cleaned by adopting ultrasonic oscillation. In the soldering paste printing process, the nano-silver soldering paste is printed by adopting metal stencil printing, and nano-silver is printed twice. In the chip mounting process, chip mounting is performed by adopting a chip mounter. In thesintering process, sintering is performed by adopting a vacuum reflow furnace to obtain an oxygen-free atmosphere of formic acid, and a sintering temperature and a heating rate are controlled. The dense connection between the nano-silver soldering paste and the bare DBC can be realized and the bare DBC can be prevented from being oxidized. No special equipment is required; the treatment process isconvenient and easy; the process is simple; a power chip can be connected with a bare copper substrate or a copper-clad substrate through the nano-silver soldering paste; the reliability of subsequent lead bonding is ensured; the reliability of a power module is improved; and the application of the nano-silver soldering paste to the power semiconductor module packaging is greatly facilitated.