Viscose fiber templates (15 cm×15 cm×1 cm) were put into ZrOCl2 solutions of different concentrations (1, 2 and 3 mol·L-1) and impregnated at different temperatures (20, 40 and 60 ℃) for 20 h. After washing, centrifugation and drying, ZrO2 fiber precursors were obtained. ZrO2 fibers were prepared by heat treatment of the precursors at different temperatures (600, 800, 1 000 and 1 200 ℃) for 2 h. The effects of the impregnation temperature, the impregnation solution concentration and the heat treatment temperature on the microstructure and the phase composition of the ZrO2 fibers were studied. The results show that with the increase of the impregnation temperature from 20 ℃ to 60 ℃ and the impregnation solution concentration increase from 1 mol·L-1 to 3 mol·L-1, the microstructure of fiber cross section changes from flat to cylindrical, and the average fiber diameter increases, indicating that the increase of the impregnation solution concentration and the impregnation temperature is beneficial to increasing the adsorption capacity of Zr4+ on viscose fiber templates. After heat treatment, ZrO2 fiber mainly exists in the form of monoclinic ZrO2. With the increase of the heat treatment temperature, the grains in ZrO2 fibers become larger and the crystallinity degree increases, meanwhile the fiber surface undergoes a transition from smooth to small grains and then to cracks.