The majority of the energy consumption by the sensors is the energy requirement for data transmission in Wireless Sensor Networks (WSNs).Therefore,introducing mobile collectors to collect data instead of multi-hop data relay is essential.However,for many proposed data gathering approaches,long data delay is the main problem.Hence,the problem of how to decrease the energy consumption and the data delay needs to be solved.In this paper,a low delay data collection mechanism using multiple mobile collectors is proposed.First,a self-organization clustering algorithm is designed.Second,sensor nodes are organized into three-level clusters.Then a collection strategy based on the hierarchical structure is proposed,which includes two rules to dispatch mobile collectors rationally.Simulation results show that the proposed mechanism is superior to other existing approaches in terms of the reduction in energy expenditure and the decrease in data delay.