Plasma nitriding combined with pulsed bias arc ion plating was employed to treat cast pure titanium (PT) used as a kind of medical and dental materials in order to improve the surface properties and to obtain better the color stability. The morphology and phase structure of the modified layer were analyzed using XRD and SEM. The contact angle and color of the samples were studied after ion nitriding/TiN-coated compound treatment (compound nitriding, CN) by Easy Drop Standard and spectraphotometer, respectively. The results show that a composite gradient TiN coating, which is uniform, stable and dense, is formed after CN. The contact angle of the artificial saliva on samples treated by CN (60.29±2.00)° is obviously lower than that of the untreated PT samples (73.12±3.29)°. And the color of CN samples with L*: 61.22±0.455, a*: 1.84±0.055, b*: 25.66±0.219 in CIE-1976- L*, a*, b* colorrange system is bright and golden. The main phases on the specimen surface are TiN and Ti2N with good wear resistance.