The invention discloses a nonsynchronous fault range-finding method for a double-circuit line, comprising series compensation, on the same tower, and the method comprises the steps: employing a six-sequence component method for decoupling for each sub-algorithm, and eliminating a series compensation voltage at a side nearby a fault and series compensation currents at two sides in a transmission equation according to the characteristics that the voltages, deduced from two sides, of a fault point are equal and the currents at two sides of a series compensation device meet the Kirchhoff's Current Law; constructing a fault positioning function through employing the pure resistance of a transition resistor at the fault point when the double-circuit line on the same tower comprises the series compensation; inputting double-end data into an M-side sub-algorithm and an N-side sub-algorithm at the same time for calculation, and directly achieving the precise positioning of a fault without the discrimination of a fault section. The method is applicable to all types of faults, does not need to carry out synchronous sampling, is independent of a series compensation device model, is not affected by MOV nonlinearity, does not need to know the position of the fault point relative to the series compensation in advance, is simple in range-finding principle, just needs to carry out the one-dimensional search of the fault distance, and does not have a problem of false root discrimination.