Currently the method can only calculate the capacitance of simple and regular capacitor in electromagnetic.In this study,the actual problems associated with the complex capacitors are investigated and classified.Therefore,a method of mending by replacing a damaged part and a method for integral on the conclusion are proposed to calculate the capacitance of complex capacitor.The second method can also be classified as the conclusion integral method for parallel capacitor and the export conclusion integral method for generic.The study greatly contributes to the theory for calculating capacitance of capacitor by extending the export conclusion integral method for generic to calculate the more perplexing capacitor.