The invention relates to a high-reliability plate type muffler. The high-reliability plate type muffler comprises a smoke charging pipe (1), a housing (5) and a smoke discharging pipe (6), and is characterized in that two U-shaped partition plates (4) are arranged inside the housing (5) of the muffler; the two U-shaped partition plates (4) are arranged oppositely and are integrally welded by usingan upper connecting plate (3) and a lower connecting plate (3); the U-shaped partition plates (4) are welded on the smoke charging pipe (1) by using a fixing plate (2); and the smoke charging pipe (1) and the smoke discharging pipe (6) are each of a small-hole type muffling pipe of which the tail end is sealed, and are correspondingly welded at the front and rear sidewalls of the housing (5). According to the muffler provided by the invention, an internal muffling structure and the upper and lower surfaces of the housing are free of any welding spots, so generation of cracks is prevented, theproblem about leakage of general mufflers is solved, and the high-reliability plate type muffler is especially applicable to the fields such as small-size noiseless generator sets which are high in requirements on silence performance and reliability.