This study attempted the development of surface finishing material for parking slab mixed with cementitious powder component to polyurethane resin, which is composed of four ingredients like A(modified polyol), B(polyisocyanate), $H_2O$ and powder mixture. Through preliminary experiments, samples were made with eight different amounts of the powder mixture keeping the same amount of other three ingredients like A, B, and $H_2O$. After placing these samples in the thickness of about 1.50mm, one sample was selected which had no different color and cracks on the hardened surface. The selected sample was tested about flow, flexural strength, compressive strength, bond strength, watertightness, impact resistance, and wheel-moving load resistance. The results were analyzed and examined to present the usability as a surface finishing material for parking slab with the optimum composition ratio. As the results of the experiments, it was found that there was no different color and crack on the surface of the hardened sample which had the composition ratio of A : B : $H_2O$ : Powder Mixture = 1 : 2 : 0.6 : 3.43. Also, this sample satisfied the quality standard regarding dynamic wheel load resistance, flexural strength, compressive strength, bond strength, impact resistance and watertightness which are prescribed by KS F 4937 and KS F 4041. As conclusion, this study confirmed that the polyurethane based mortar in the above composition ratio could be an optimum surface finishing material usable for parking lot slab floor.