Ever since the concept of swarm intelligence was brought out,a variety of control algorithms for swarm robotics has been put forward,and many of these algorithms are stable enough and efficient.Most of the researches only take an invariable controller which functions through the whole stage into consideration,the situation in which controller changes over time is rarely taken into account.However,there are limitations for invariable controller dominated algorithms in practical situation,which makes them unable to meet changing environment.On the contrary,variable controller is more flexible and can be able to adapt to complex environment.Considering such advantages,a time-varying algorithm for swarm robotics is presented in this paper.The algorithm takes time as one of the independent variables so that the controller is no longer fixed through the time,but can be changed over time,which brings more choices for the swarm robot system.In this paper,some relevant simulations are designed to test the algorithm.Different control strategies are applied on the same flock during the time,and a more complex,flexible and practical control effect is acquired successfully.