The fractal characterisitcs of two-dimensional projected real electrical tree grown at the tip of the needle electrode in DGEBA-MDA-SN system were investigated. The treeing tests were carried out in a needle-plane electrode geometry under AC high electrical stress application. The fractal dimensions of tree patterns were investigated by using a scale covering method. The electrical trees grown in DGEBA-MIDA-SN system under high electric field were fractal objects, and the fractal dimension increased with increasing tree length and saturated at 1.5~1.6