The invention relates to an oil drainage pit silencing device for reducing noises in a transformer chamber. An oil drainage pit is formed just below the transformer chamber; a shutter is arranged at the front side of the oil drainage pit; the oil drainage pit silencing device comprises six silencing sheets which are arranged in parallel, wherein each silencing sheet is perpendicularly mounted a bottom plate of the oil drainage pit; the height of each silencing sheet is equal to the free height of the oil drainage pit; the six silencing sheets are uniformly arranged in the oil drainage pit from the left to the right in a spaced manner; the left side surface of the silencing sheet at the leftmost side is flush with the left side surface of the shutter; the right side surface of the silencing sheet at the rightmost side is flush with the right side surface of the shutter; the front side surface of each silencing sheet is tightly adhered to the rear side surface of the shutter. The oil drainage pit silencing device disclosed by the invention is relatively good in noise reducing effect and does not affect ventilation and heat dissipation of the transformer chamber of a 10kV transformer and power distribution station.