The invention provides a rectifier type intrinsically-safe Buck circuit which comprises a main circuit and four limiting circuits. The main circuit comprises a power supply E, a switch tube S, a diodeD, an inductor L, a capacitor C and a resistor R; the switch tube R is connected with the inductor L via a second line; the inductor L is connected with the resistor R via a third line; the resistorR is connected with the power supply E via a third line; the diode D is connected between the second line and the fourth line; the capacitor C is connected between the third line and the fourth line;and the four limiting circuits are connected to the first to fourth lines respectively. The circuit structure is simple, open-circuit spark is rectified, the capacitance is inhibited, and a diode voltage is clamped, so that the circuit cannot form dangerous open-circuit sparks from beginning to end, arcs cannot be formed fundamentally, and the intrinsically safe performance of the circuit is improved further.