Abstract:A finite element model of rod porcelain insulator containing semi-elliptical surface crack was established in ANSYS solid modeling method. Three dimensional 20 node isoparametric degenerative singular elements were used to simulate the stress singularity of the crack tip, and the stress intensity factor (SIF) of crack front on porcelain insulator under bending was calculated in 1/4-node method. The rule of crack size, location and various load versus KI was obtained. The results have shown that, under the same condition, the maximum of crack front SIFs appears at the deepest point between the lower flange port and the first umbrella skirt, and the value of KI decreases with the increase of crack shape ratio, while increases with the increase of crack depth and load.