For studying the adaptability of single terminal traveling wave protection in mid-voltage DC distribution based on VSC (voltage sourced converter), firstly the best working condition is obtained by analyzing the principle of singe terminal traveling wave protection, the general protection adaptability conclusion is reached by theoretical analysis based on the condition and the fault characteristics of DC distribution lines. Then, the electrical-magnetic model of DC distribution network is established and simulated, and the simulation results are compared with theoretical analysis results. The research shows that the single-terminal traveling wave protection can apply to VSC-based mid-voltage DC distribution line with good performance. The correctness of theoretical analysis is verified by simulation results. This work is supported by National Natural Science Foundation of China (No. 51477131).