The amorphous Co-based magnetic films have a large saturation flux density, a low coercive force, and a zero magnetostriction constant. Therefore, they have been studied for application to magnetic recoding heads and micro magnetic devices. However, it was found that the magnetic anisotropy was changed for each film fabrication processes. In this study, we investigated how to control the anisotropy of sputtered amorphous $Co_{89}Nb{8.5}Zr{2.5}$ films. After deposition, the rotational field annealing ant the uniaxial field annealing were performed under the magnetic field of 1.5 kOe. the annealing was done at the temperature range from 400 to $600^{circ}C$ for one hour. As-deposited amorphous $Co_{89}Nb{8.5}Zr{2.5}$ thin film had saturation magnetization ($4piM_5$) of 0.8 T, coercive force($_IH_C$) of 1.5 Oe, and anisotropy field($H_k$) of 11 Oe. The amorphous $Co_{89}Nb{8.5}Zr{2.5}$ thin films annealed by rotational field annealing at $500^{circ}C$ for one hour was found to be isotropy, and $4piM_5$ of 0.9 T was obtained from these films, Also, the magnetic anisotropy of as-deposited films could be controlled by uniaxial field annealing at $400^{circ}C$ for one hour. Anisotropy field($H_k$) of 17 Oe and $4piM_5$ of 1.0 T were obtained by this method.