Based on distributed parameters, a new location method is presented for phase-to-phase fault on three-terminal HV transmission line by using electric data at terminals. The fault voltage is calculated by the voltage and current data measured from the protection. The fault location function is provided, of which the phase characteristics are applied to decide the fault section. The only step point for the phase of fault location function corresponds to the fault position. As a result, the method avoids the distributed capacity effect by modeling with distributed parameters, the load current effect by considering fault voltage, and the transition impedance effect by phase step of fault location function. It is shown from the simulation by PSCAD/EMTDC that the method is of high range accuracy, regardless of fault location, transition impedance and load current.