The utility model belongs to the technical field of water stopping of steel sheet pile cofferdams, and particularly relates to a simple water stopping device of a shoal steel sheet pile cofferdam affected by tidal level, which resolves problems that the existing steel sheet pile cofferdam water stopping method is inconvenient in operation and poor in use effect. The simple water stopping device of a shoal steel sheet pile cofferdam affected by tidal level comprises a plastic film coated on the outer side of the steel sheet pile cofferdam, the upper end of the plastic film is connected with steel sheet piles while the lower end thereof is buried into a river bed, and cotton fibers are plugged in joints of the steel sheet piles inside the steel sheet pile cofferdam. The simple water stopping device has the advantages that 1, the simple water stopping device adopts a simple, fast and feasible cofferdam water stopping method, and 2, the simple water stopping device utilizes the plastic film as water stopping materials, and is low in cost and simple in operation.