Three physical parameters such as the difference in atomic size ratios (△d), the difference of atomic electronegativity ratios (△e) and the ion ratio (v) were calculated by using the weighted average principle on the basis of the present BMG. The critical cooling velocity for forming glass (R_c) of the bulk metallic glass (BMG) was applied as the target parameter for the evaluation of the glass forming ability (GFA). The relation between the three related parameters and R_c was determined by using Origin, the results showed that a minimum was found in the relations between R_c and △d， △e and v，and for different alloy systems, the minimum positions were different one another. As for the BMG with higher GFA, the relations among atom percent, the difference of atomic size ratios and the difference of atomic electronegativity ratios between atom pairs were harmonious. The optimum compositional range of BMG and the optimum addition ratio of additive elements may be related to the minimum phenomena of the relation between three related parameters and Rc.