Subway entrance flood prevention plate capable of being automatically opened

The utility model discloses an automatic opening subway entrance flood prevention plate which comprises a foundation layer, a lower water storage channel and a flood prevention plate, the lower water storage channel and the flood prevention plate are arranged in the foundation layer, the lower water storage channel is located below the front portion of the flood prevention plate, and a floor drain opening covers the ground at the top of the lower water storage channel. A floor drain opening is formed in the ground above the lower water storage channel, the water level in the lower water storage channel rises, a floating block floats upwards, a first metal sheet arranged above the floating block floats upwards and then makes contact with a second metal sheet, a contact wire is used for external control, a motor is made to rotate, a first gear is driven to rotate, the first gear is meshed with a tooth surface, and therefore a flood prevention plate can rise; on the contrary, after the rainfall becomes smaller,