The invention discloses a method for determining the turn-to-turn short circuit, two-phase short circuit and single-phase short circuit of parallel reactors, which comprises the following steps: (1) calculating a fault component delta*2 of a negative sequence voltage according to measurement; (2) calculating a fault component delta*2 of a negative sequence current according to measurement; (3) substituting the delta*2 and the delta*2 into a formula (A) expressed as the absolute value of (delta*2-jdelta*2XL2) is more than or equal to the absolute value of (delta*2+jdelta*2XS2), wherein the formula (A) is an operational equation of a voltage absolute value comparison type negative sequence directional relay, and in the formula, XL2 represents the negative sequence reactance of the reactors and XS2 represents system negative sequence reactance; and (4) if the formula A is valid, determining that parallel reactors having ungrounded neutral points have an internal turn-to-turn short circuit or two-phase short circuit fault, and if the neutral points of the parallel reactors are directly grounded or grounded by small reactors, determining that the parallel reactors directly grounded or grounded by small reactors have an internal turn-to-turn short circuit or two-phase circuit or single-phase circuit fault. The method is mainly used for relay protection devices of high-voltage parallel reactors.