Objective To prepare a bio-collagen coating on pure titanium surface and investigate its effect on osteoblast differentiation. Methods The type I collagen was made into gel and adhered to the surface of pure titanium specimens to form bio-collagen coating. The smooth titanium surface was used as the control group, the collagen coated titanium surface was used as the experimental group. The surface microtopography of specimens was observed by scanning electron microscopy (SEM), the surface elemental compositions of specimens were analyzed via X-ray photoelectron spectroscopy (XPS), the groups on specimen surfaces were detected with fourier transform infrared spectrometer (FT-IR), and the surface hydrophilicity of specimens was tested by water contact angle meter. The adhesion, proliferation and differentiation of osteoblasts on titanium surfaces were evaluated by laser confocal microscopy, CCK-8, ALP and western blot after the osteoblasts (MC3T3-E1) were cultured in vitro. Results SEM observation found a coating-like structure on the surface of experimental specimens. XPS elemental analysis and FT-IR detection confirmed that the structure was a collagen coating. Water contact angle results showed that the experimental group had better surface hydrophilicity than the control group. The results of in vitro study exhibited that collagen coated titanium surface could promote the adhesion and proliferation activity of osteoblasts and up-regulate ALP activity as well as the expressions of osteogenic functional proteins including Runx2, osterix and OCN. Conclusion The modification of collagen gel coating on pure titanium surface can enhance its hydrophilicity and promote adhesion, proliferation and differentiation of osteoblasts.