In this paper, the internal fuse of shunt capacitor which was BAM6.56-556-1W used in AC UHV project had been designed and calculated. Combined with the method of energy calculation and fuse current density, the fuse model with Φ0.42×160mm was chosen. In order to test the characteristics of the internal fuse , based on the improvement of the internal fuse parameter, the test sample capacitor was designed and tested according to experimental plan which was stricter than GB/T 11024.1-2010, GB/T 11024.1-2001, DL/T840-2003, etc. The result indicated that the revised-design internal fuse which was used in BAM6.56-556-1W sample capacitor had passed all verification test items. Compared with the requirement of standard, the short-circuit discharging voltage was increasing by 30%, the upper limit voltage of fuse insulating test was increasing by 30%, the range of lower limit voltage was increasing 10%, the withstand voltage of the fuse fracture was increasing 30%. The internal fuse which was verified by test was helpful for the safe and reliable operation of the shunt capacitor installation used in AC UHV project.