Elliptical plate capacitor made of slots in the elliptical cylindrical plate is a form of capacitor. In this　paper，the conformal mapping method is used to solve the capacitance value of the symmetric elliptic cylinder plate capacitor with different slit width.Using the method of Zhukovsky transformation，we convert a symmetric elliptic cylindrical capacitor to a symmetrical arc - cylindrical capacitor. The capacitance of slotted elliptic cylindrical capacitor with different slit width is found out in terms of the results of the symmetrical arc-cylindrical capacitor reference from the literature.