The invention provides a method and device for analyzing the appearance of an organic external insulation surface, relating to the technical field of power systems. The method comprises the followingsteps: acquiring scanning data of the organic external insulation surface in a measurement plane, and setting a projection plane; determining a fractal structure judgment cube according to iteration parameters; covering the projection plane with the fractal structure judgment cube, and determining whether the projection area of the projection plane is larger than the projection area of the projection plane in the measurement plane; if the projection area of the projection plane is less than or equal to the projection area of the projection plane in the measurement plane, cutting the projectionplane, determining the number of covered cubes corresponding to a current iteration parameter, updating the iteration parameter, and returning to update the fractal structure judgment cube; if the projection area of the projection plane is larger than the projection area of the projection plane in the measurement plane, determining a linear regression relationship according to the number of the covered cubes corresponding to each iteration parameter and the side lengths of the fractal structure judgment cube so as to obtain a slope absolute value, and determining a fractal upper limit scale;and determining the fractal dimension of the organic external insulation surface according to the fractal upper limit scale. According to the method, the fractal features of the organic external insulation surface can be accurately analyzed.