As the last threshold of urban drainage,only safe and reasonable design can ensure the normal operation of the entire drainage system,so as to avoid water accumulation and urban waterlogging in the upper reaches of the city.Taking the design of a sea discharge pipe culvert in Xiamen City as an example,the sea discharge pipe culvert was calculated and analyzed according to the catchment area,runoff coeficient,return period,pipe diameter,slope,head loss,overflow capacity and other parameters,and the design of the sea discharge pipe culvert was carried out according to the site conditions.