The sliding wear behavior of the plasma-sprayed zirconia containing 3 mol% yttria was investigated after the annealing at room temperature to 80$0^{circ}C$ in various concentrations of humid atmosphere as laboratory, humid, dry argon atmosphere. Both of the friction coefficient and the wear loss increased with increasing temperature up to 80$0^{circ}C$. Surface morphology of the worn samples changed with annealing temperature. The change of monoclinic/tetragonal (m/t) x-ray peak intensity ratio effected the wear behavior. The m/t ratio had maximum value at 20$0^{circ}C$ and decreased with increased temperature in laboratory and humid atmosphere. In argon atmosphere the m/t ratio had no maximum value and decreased with increasing temperature. At all the annealing temperature humid atmosphere had more the m/t ratio value than any other atmosphere. The change of toughness was showed the inversed result of m/t ratio change. The results indicated that the resudial stress which was induced by the different amount of phase transformation takes a detrimental role in wear behavior.