The invention provides a synchronous lining device and method for a sewage tunnel. The device comprises a main machine and a trolley. A duct piece mounting machine is arranged in the main machine; anda duct piece conveying device is arranged between the duct piece mounting machine and the trolley. The trolley slides on a bottom special duct piece and is provided with at least one template longitudinal baffle; and the first template longitudinal baffle is connected with a template front baffle. A concrete grouting machine is arranged at the trolley. In addition, the method includes the following steps that: a duct piece and a bottom special duct piece are spliced in an annular manner; pre-stage concrete is poured in the space between a template longitudinal baffle and the duct piece, a template front baffle is arranged at the front end of the first template longitudinal baffle, and the bottom duct piece is paved completely after the trolley. The synchronous lining device and method have the following advantages: the overall structure is simple; the interference on the supporting construction is low; secondary support is carried out directly on the duct piece, so that the procedureof roughening on the inner wall of the traditional concrete duct piece is saved and thus the post-stage construction procedures are reduced. The good economic, efficient, simple and practical effectsare realized.