When a DC fault occurs in a flexible photovoltaic DC collection branch, the transient process is rapidly changing. Thus it is difficult to apply traditional fault location methods based on fixed characteristic frequency impedance measurement. Therefore, it is urgent to study fast and reliable fault location methods to quickly achieve photovoltaic DC collection system recovery. This paper proposes a bipolar short-circuit fault location method based on high-frequency resonance identification. It uses the step characteristics of the DC fault pole-to-pole voltage and the series resonance of a DC Transformer (DCT) outlet parallel capacitor and a current-limiting reactor. The relationship between the resonance current and the fault distance is extracted by Continuous Wavelet Transform (CWT), the fault distance is calculated, and the fault location is finally completed. Compared with the traditional fault location method, this method does not require additional high-frequency injection sources and is not affected by the state of the converter and the control system. PSCAD simulation results show that the proposed method only needs 2.5 ms of fault data before and after the fault to perform reliable fault ranging. The required data window is short, which meets the requirements of photovoltaic DC assembly to accurately locate faults and quickly resume operation, and the method is capable of withstanding transient resistance, noise, and distributed capacitance. This method provides a new alternative to existing DC system protection designs. This work is supported by the Science and Technology Project of State Grid Corporation of China “Research on Fault Characteristics and Protection of Hybrid AC/DC Distribution Network” (No. 2019-LHKJ-017).