As a new anti-erosion structure, Reynolds mat often faces the underwater construction while it is used in the channel bank protection, bottom protection and surface protection of the dam and other projects.This paper summarizes the underwater construction methods of Reynolds mat and discusses the feasibility and effect of the underwater construction by the trailing method for Reynolds mat taking the waterway regulation training works of Zhoutian river section in the middle reaches of the Yangtze River as a study case. It may serve as a reference for the engineering design and construction.