Objective To study the effects of surface roughness and titanium dioxide（TiO2） layers on commercially pure titanium（cp-Ti） substrates on attachment of osteoblasts in vitro. Methods 250 pure titanium slices were divided into five groups. Osteoblasts were cultured on five cp-Ti substrates of ground, which blasted with 108-130 μm（S1）, 216-301 μm（S2）, 356-411 μm（S3） TiO2 particles and titanium-sprayed plasma（TPS） surfaces, surfaces prepared by hand grinding with SiC paper to 600 grits served as control（S0）. Surface average roughness and the TiO2 film structure was evaluated. For morphology and attachment measurement, osteoblasts were cultured for 1, 4, 12 and 24 h, evaluated by scanning electronic microscope（SEM） observation and MTT assay. Results Osteoblasts spread well on the titanium surfaces. Further more, osteoblasts spread more well on S3 surfaces. After 1 and 4 h culture, the number of cells on S3 surfaces was the highest（P0.05） as TPS surfaces and higher than other groups（P
