Dual-band thermal emitters with narrow bandwidths have important applications potential in many fields such as infrared sensing，encryption and detection.This emitter can provide concentrated. However，the conditions for construing narrowband emission in different wavelband usually conflict with each other， making it difficult to achieve dual-band narrowband thermal emitters. In this paper， a new type of lithography-free infrared dual-band thermal emitter is proposed， which consists of alternately deposited Ge and YbF₃ films on Al films. The narrowband emission characteristics stem from the Tamm plasmon polaritons （TPPs） that can be excited by the distributed Bragg reflector and the Al substrate under certain conditions. The geometric parameters are optimized using multi-objective particle swarm optimization algorithm. The experimental results confirm that dual-band emitter can simultaneously exhibit narrowband emitter characteristics in both mid-wave infrared （MWIR） and long-wave infrared （LWIR） regions. The proposed method can be used in the design of multi-band emission modulation devices， which can be applied to the fields of multi-gas sensing and multi-band infrared camouflage.