Abstract: The microstructures of hot extruded tubes, cold rolled tubes and annealed tubes of Zr-0.2Sn-1.3Nb-0.2Fe-0.05V alloy cladding tubes were studied with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results show that β-Zr and second phase particles (SPPs) tend to precipitate along the direction of deformation after hot extrusion. With processing and heat treatment for the alloy, β-Zr tends to be decomposed, and the size and distribution of SPPs become more and more homogeneous. β-Nb with BCC structure and Zr(NbFeV)₂ with FCC structure are found in the products. Average size of SPPs of every process stage doesn’t change much and is under 100 nm. The size and distribution of precipitates in Zr-Sn-Nb-Fe-V alloy cladding tube are closely related to decomposition and precipitation of SPPs containing Nb during heat treatment.