The invention discloses a low-ripple wave filtering device which comprises a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, an inductor L1, an inductor L2 and an inductor L3. The capacitor C3, the inductor L1 and the capacitor C4 are sequentially serially connected with one another to form a closed circuit; the capacitor C2 is connected to two ends of the capacitor C3 in parallel, the capacitor C1 is connected to two ends of the capacitor C2 in parallel, the capacitor C5 is connected to two ends of the capacitor C4 in parallel, and the capacitor C6 is connected to two ends of the capacitor C5 in parallel; the inductor L2 is connected to two ends of the inductor L1 in parallel, and the inductor L3 is connected to two ends of the inductor L2 in parallel; a common end of the capacitor C1, the capacitor C2, the capacitor C3, the inductor L1, the inductor L2 and the inductor L3 is connected with an input end Vin; a common end of the capacitor C4, the capacitor C5, the capacitor C6, the inductor L1, the inductor L2 and the inductor L3 is connected with an output end Vout. Owing to the principle, the low-ripple wave filtering device has the advantages that direct-current ripple waves in filter signals can be effectively reduced, high-frequency interference can be decreased, and accordingly signals transmitted by microwave circuits are stable.