On the basis of current measuring principle of Rogowski coil, relevant mathematical models were set up, which were about electromagnetic induction ability of coils affected by their structure parameters when their frame sections were circular and rectangular. Then, simulation studies were carried out, results showed that relative error of mutual inductance of the circular coil was smaller, which was helpful for obtaining more accurate current values, Increasing the frame diameter and center diameter of coil could enhance induction signal of the coil, but the ratio values of the two must be under controlled. Finally, selection method of structure parameters of Rogowski coil were put forward, and the validity of these studying results were verified combining with instances, which provided powerful guidance for selecting Rogowski coil rapidly and reasonably.