Understanding of electrical performance for Si/Si bonding structure is of great importance for both study of interface and fabrication of micro-electronic elements. We firstly analyzed I-V performance for different Si/Si bonding structures, and then using SOS model made capacitance curve-fitting for n-Si/n-Si structure. Comparing theoretical curve with experimental data, we got shifting voltage VFB and interfacial states density Din. These results availed to study the interface of silicon bonding structure.