One-kilometer directional drilling rig is a head-type hydraulic rig, which can drill horizontal deep holes in coalseam with down-hole motor for gas drainage. To avoid the hole axis floating and the rig overturning, a stabilizer is designed for high stable ability in this paper. Stabilizer is subsequently modeled and simulated in four typical conditions where the drilling rod rotates. The result shows that the new stabilizer has larger rigidity and is safe.