This paper focuses on the problem of coordinated path following for underactuated unmanned surface vehicles (USVs) based on distributed control with directed topologies. First, a finite-time extended state observer is presented to estimate the velocities and model uncertainties, simultaneously. Second, a finite-time line-of-sight based guidance law is proposed for individual USV in kinematic loop to track the desired path. Specifically, a cooperative update law for the path variable is designed under one-way communication, such that all USVs maintain the same distance from each other along one curve, following a virtual leader. Then, a control subsystem is proposed by combining a novel auxiliary dynamic system and sliding mode technique for each vehicle at the kinetic level, where the auxiliary dynamic system is developed to ensure the finite-time stability of the entire system while to solve saturation problem. The closed-loop system is verified to be uniformly global finite-time stable. Finally, the numerical simulations substantiates the feasibility of the proposed coordinated path following strategy.