In order to study the characteristics of zero sequence voltage signal change during tree line fault, an experimental platform for tree line fault is built to study the zero sequence voltage variation characteristics when single-phase tree line ground fault occurs in different vegetation under different residual currents in the resonant grounding system. The change stages and laws of the zero sequence voltage are summarized and the influence laws of the residual currents and vegetation's own parameters are analyzed on the change of the zero sequence voltage. Based on this, the prediction model for the peak value of the zero sequence voltage is built. The experimental results show that the development process of tree line fault can be expressed by the zero sequence voltage variation, which typically exhibit four stages: slow increase, rapid increase, decline and recovery. The trend of these changes follows three types of curves: U-shaped, J-shaped, and V-shaped. The increase of residual current will lead to a decrease in the amplitude of the zero sequence voltage change, which is not conducive to the detection of faults, and its value should be compensated to the range of 0~1 A as much as possible. For the same kind of vegetation, the peak zero-sequence voltage is positively correlated with the water content and diameter, and the peak time is negatively correlated with both of them. The structural difference of different kinds of vegetation is also the key to influence the peak zero-sequence voltage and peak time. The results of this study are of great significance for the detection and early warning of hill fires caused by tree line faults.