The Co48Cr15Mo14C15B6Er2 amorphous ribbon and rods with diameters of 2mm and 7mm were prepared by melt spinning and copper mold casting. The different Scanning calorimetry and the vibrating sample magnetometer were employed to investigate the effect of cooling rate on crystallization kinetics and magnetic properties of metallic Co48Cr15Mo14C15B6Er2 glass. It was found that the cooling rate had significant influence on the crystallization kinetics. In the case of non-isothermal crystallization process, the glass transition temperature and the activation energy for the glass transition decreased with decreasing of cooling rate. The activation energy for crystallization also decreased with decreasing of cooling rate, in despite of that the peak temperature of crystallization was independent of cooling rate. Although the isothermal crystallization was governed by diffusion-controlled three-dimensional growth with decreasing of nucleation rate for Co48Cr15Mo14C15B6Er2 glasses under different cooling rates, how rapidly the nucleation rate decreased was related to cooling rate. The more rapid the cooling rate was, the faster the decrease of the rate was. The magnetic properties of Co48Cr15Mo14C15B6Er2 glass was significantly affected by cooling rate. The sample obtained at high cooling rate took on paramagnetic property, whereas the sample obtained at low cooling rate took on ferromagnetic property. The saturation magnetization increased with decreasing of cooling rate.