Cracks on the surface layer concrete, the influence factors of appearance quality of the project and reducing the durability of the structure, are common quality problem in the construction of pile-supported wharf.It is necessary to study the causes of cracks in the surface layer of the wharf and take targeted control measures.We introduce the structural design, construction technology and cracks in the concrete surface layer of the test section of a pile-supported beam-slab wharf in East Africa, and use simulation calculations of concrete structure shrinkage stress and on-site investigation to analyze the crack causes that are drying shrinkage caused by water loss and plastic shrinkage caused by poor curing.Then we propose control measures from the aspects of optimizing raw material quality, optimizing concrete mix ratio, and improving construction technology, etc.In the subsequent typical construction, the amount of surface concrete is reduced by 98% and the maximum width of cracks is decreased by 60%.The control effects are well.