Data gathering is the basic function of the sensor networks.However,the existing gathering schemes are almost based on the architecture with a static base station which results in the quick death of nodes around the base station.The reason is that the sensor nodes located near a base station have to relay data for a large part of the network and thus deplete their batteries very quickly.This paper discusses how to use the mobile base station for data gathering with load-balancing.A data gathering scheme MADG(movement-assisted data gathering),which makes use of the mobile base station for data collection,is presented.In this scheme,the base station moves in a stationary annularity area exploited for data buffering.The gathered data.are firstly forwarded into the buffering area and then collected by the mobile base station.It is theoretically proved that the location 2~(1/2)R/2 away from the center is the optimal location for minimizing the energy consumption for transmitting data and that there exists a location which can make the maximal node load minimize.This paper then considers the optimum location jointing the energy consumption and load-balancing based on above analyses.Compared with the static base station scheme and the existing mobile base station scheme,MADG reduces the load by over 95% and 80%,respectively.