The utility model discloses a receiving circuit in ETC (electronic toll collection) on-board equipment and on-board equipment, wherein the receiving circuit in ETC on-board equipment comprises a power supply; a first stage of triode, wherein the base thereof is connected with an antenna via a first coupling capacitor and simultaneously connected with the power supply via a plurality of resistors, the collector thereof is directly connected with the power supply, and the emitter is grounded via a plurality of resistors; a second stage of triode, wherein the base and the collector thereof are connected with the power supply via a plurality of resistors respectively, the emitter thereof is grounded, and the base thereof is connected to the emitter of the first stage of triode via a second coupling capacitor; a third stage of triode, wherein the base thereof is connected with the power supply via a plurality of resistors, the collector thereof is directly connected with the power supply, the emitter thereof is grounded via a plurality of resistors, and the base thereof is connected to the collector of the second stage of triode via a third coupling capacitor; and a comparer, wherein on one hand, the emitter of the third stage of triode is connected with the opposite-directional terminal of the comparer via a first resistor; on the other hand, the emitter of the third stage of triode is connected with the same-directional terminal of the comparer via a passive low-pass filter circuit.