Zirconium alloys are used as the fuel cladding materials in nuclear power reactors. Corrosion resistance is one of the most important factors for the application of zirconium alloys, which involves the lifetime of fuel assembles, and the safety and reliability of the operation for nuclear power reactors. According to the current research, the characterizations of precipitates in zirconium alloys affect the corrosion resistance significantly. However, the investigation results about the precipitates in zirconium alloys are variable. Zr-4 (Zr-1.2Sn-0.2Fe-0.1Cr), E110 (Zr-1Nb) and Zirlo (Zr-1Sn-1Nb-0.1Fe) are commercial alloys to be widely applied for pressurized water reactors(PWRs). Zr-4, E110 and Zirlo, as the representatives of Zr-Sn, Zr-Nb and Zr-Sn-Nb alloys, are widely applied for PWRs. Three alloys were developed in the early time, and there are many data and experience for the performance in reactors As the references. Three alloys are studied and the precipitates and microstructures are systematically analyzed. The transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and High-resolution transmission electron microscopy (HRTEM) have been used to study the composition, structure, defects and orientation relationship of the precipitates in commercially available Zr-based alloys.