In order to solve those problems, for example high precision synchronization requirements, heavy traffic, and uncertainty of wave velocity, and at the same time improve the tolerance rate and reliability of the location system, this paper presents a new method for single-terminal traveling wave location with amended wave velocity by two-terminal asynchronous data. By analyzing the changes of polarity of the wave after catadioptric and introducing zero-modulus and line modulus wave velocity contrast as auxiliary criterion, it counts the time-lag between initial wave and reflected wave from remote bus under receiving disturbance, then amends the value of wave velocity through this time-lag of two terminals, finally uses the amended velocity and time-lag of single terminal to locate the fault accurately. This algorithm integrates the advatages of single-terminal data easy to time synchronization and two-terminal data amending the wave velocity, reduces high precision time synchronization required by the two-terminal traveling wave fault location; and at the same time two terminals only exchange time-lag of single terminal, which will reduce the communication dependency. PSCAD/EMTDC simulation show that this method has high precision for fault location, and also decreases the negative influence made by wave velocity and time synchronization. This work is supported by National Natural Science Foundation of China (No. 51507091).