The growth of electrical tree in cross-linked polyethylene (XLPE) cables is accompanied by the generation of partial discharges (PD), and there is a correlation between the both. The rise time of the PD signal in XLPE with high dielectric strength is short, so the signal amplitude in the super high frequency (SHF, 3~30 GHz) band is large. In this paper, the defect sample based on needle-plate electrode structure and XLPE insulation material is applied. The morphological of electrical tree and SHF PD signals are detected synchronously during the growth of electrical tree at different temperatures and voltages. The effects of voltage and temperature on the growth of electrical tree and SHF PD signals are analyzed and the characteristic correlation between the morphological of electrical tree and SHF PD signals in XLPE is studied. The results indicate that there is a positive correlation between the length and width of electrical tree in XLPE and temperature or voltage. The fractal dimension is usually lower at a lower voltage while it is not significantly changed with higher voltage. There is also a positive correlation between SHF PD signal amplitudes and temperature or voltage. Higher voltage leads to the trend that the amplitude of SHF signal increase firstly and then decreases to a plateau. The frequency of the signal decreases to a certain extent at a lower voltage. A positive correlation between the growth of electrical tree and the amplitude of SHF PD signals is acquired. The frequency of SHF signals also increases with a faster speed of the growth of electrical tree.