Laser micro-cladding technology is a novel method for circuit fabrication. With this method, electronic paste was disposed and sintered by laser process system to fabricate conductor. With the advantages of highly flexibility, easy design and modification, high efficiency and short cycle time, It can fabricate the conductor with minimum line width of 20 μm, which exceeds the limitation of traditional method. In previous work, the circuit fabrication on ceramic, glass and epoxy resin substrates by laser micro-cladding technology was researched. In this article, the conductor was fabricated on semiconductor (Si) substrate. Its minimum line width was about 30 μm and resistivity was at the same level with block Ag,which can satisfy the industrial requirements. The adhesion between conductor and Si substrate was at the order of MPa, which was equivalent with the traditional printing process. The experimental results also demonstrated that the conductor width increases with laser power density increasing, but decreases with the laser scanning speed. There is an optimal parameter range in laser processing. The heat treatment after laser scanning is benefit for conductor's electric performance and adhesion between conductor and Si substrate.