The correlation between the propagation of electrical tree and distributions of partial discharge(PD) pulses accompanying with electrical tree of bush type in low density polyethylene were discussed. We measured the growth of electrical tree by using optical microscope and PD data simultaneously. The PD data detected and analyzed were PD magnitude, repetition rate, average discharge power, average phase angle, and $psi$-q-n distribution pattern. The average discharge power and repetition rate of PD had good linear relation with area of tree. Repetition rate and peak discharge magnitude and width of discharge phase angle increased with the tree.