Abstract: Based on the analysis of the Quaternary geological survey data in coastal areas,using the drilling data of engineering investigation as a means of verification,we have ascertained the spatial distribution of some deep erosional paleochannel in the late Pleistocene to mid Holocene in coastal areas,and speculated on itshistorical origin;Combined with the special engineering geological characteristics and hydrogeological characteristics of the deep erosional paleochannel,we analyzed the adverse effects on the engineering construction.