Titanium alloys are important strategic structural materials with broad application prospects in the industries of aerospace, space technology, automobiles, biomedicine, and more. Considering the different requirements for the diverse applications of titanium alloys, the modification of physicochemical properties, mechanical properties, and biocompatibility are required, including novel composite materials, novel design, novel manufacturing methods, etc. In this review, the surface treatment technologies utilized on titanium alloys are summarized and discussed. Regarding surface modification of titanium alloys, the methods of laser treatment, electron beam treatment, surface quenching, and plasma spraying are discussed, and in terms of the surface coatings on titanium alloys, thermal spraying, cold spraying, physical vapor deposition, and chemical vapor deposition are also summarized and analyzed in this work. After surface treatments, information on microstructures, mechanical properties, and biocompatibility of titanium alloys are collected in detail. Some important results are summarized according to the aforementioned analysis and discussion, which will provide new thinking for the application of titanium alloys in the future.