The deformation wave height of the seawall waves in shallow water of Zhejiang region is researched. Based on the Zhejiang Seawall Engineering Technical Requirements and Calculus Principle, we derive the analytic formula for calculating directly the shallow water waves deformation, and study the shallow water deformation under the flat-bottomed sea bed, single slope of the sea bed, the segmented polyline sea-bed and three parabolic curve sea-bed waves, and give the analytical expressions for the concise calculation, to serve as reference for the engineering design and improve the design efficiency. It is verified by project examples that the precision of wave height calculation fully meets the engineering requirement.