The composite, with polyamide 6(PA6) as the matrix, graphene microchip(GNPmc) as the thermal filler, nano Ag as the laser reinforced filler, was prepared using torque rheometer and marked by 16.2 W laser power on the surface. The effect of amount of nano Ag on the thermal conductivity of GNPmc/PA6 composites and composition and content of the elements and residual carbon before and after laser marking were researched. The study finds that when the content of nano Ag is 1.5 g, the thermal conductivity of nano Ag-GNPmc/PA6 composite is 0.55 W/(m·K), the laser marker image is the clearest, the depth of laser marker image is 414.9 μm, the content of C decreases to 82.17% and O increases to 14.27%, amorphous C content increases a lot and residual C rate is 6.27%.