Objective To study the effects of TiO2 blasted and acid- etched surfaces of cp- titanium on changing composition of oxide- film and attachment and proliferation of osteoblasts in vitro. Methods cp- titanium discs were prepared and divided into 4 groups：TiO2 blasted（SB）, sandblasted and acid- etching（SLA1 and SLA2） and machinepolished surface（S0）. Scanning electron microscopy（SEM）, X- ray diffraction（XRD） and electron probe microanalysis （EPMA） were used to test surface morphology and composition of oxide - film. Osteoblasts were cultured on the titanium surface of 4 groups. MTT assay was used to measure the attachment and proliferation. Results In regard to surface roughness, average roughness for SB, SLA1 and SLA2 was obviously higher than S0. Oxygen ratio increased on SB,contrarily, it decreased on SLA. A mixture of anatase and rutile- type crystals were observed in the SB. Smaller anatase were observed in the SLA1 and SLA2. The ide thickness on SLA surface was thiner than that on the SB surface. After 1, 4, 24 hours′culture, the number of osteoblast attachment on SB surfaces was the highest（P
