The invention discloses an echoing device and an echoing method for a spliced wall system. The echoing device for the spliced wall system comprises an echoed data capturing unit used for obtaining synchronous pulse signals and to-be-displayed video data, performing first zooming on the data based on resolution ratio of the spliced wall system and number of display units, performing first splicing on position information of the spliced wall system and the synchronous pulse signals based on rank information of the spliced wall system and data after the first zooming, and further coding; an echoed data processing unit used for receiving M coded data and decoding the data to obtain M pulse signals and M to-be-echoed data, performing secondary splicing on the M to-be-echoed data based on the M pulse signals, and performing secondary zooming and frame frequency conversion based on display requirements; an echoed data display unit used for receiving data after the frame frequency conversion and displaying the data. The echoing device and the echoing method for the spliced wall system realize synchronization of echoing of the spliced wall, self-adapt to the resolution ratio and size dynamic variation of the spliced wall system in the echoing process, and are easy to realize and low in cost.