In order to enhance the global search ability of Biogeography-Based Optimization (BBO) in multi-threshold image segmentation,and improve its optimization performance,an Improved BBO (IBBO) algorithm is proposed.Firstly,a polyphyletic migration operator is introduced,which can better generate new eigenvalue from the searching space and effectively improve the population diversity.Secondly,a new dynamic mutation operator is created,which can dynamically change the mutation range and improve the operation efficiency of algorithm,enabling the algorithm to quickly converge to the global optimum.Then,a greedy selection operator is used instead of the original elitist selection operator,to accelerate the convergence process by using the strategy of survival of the fittest.Finally,IBBO algorithm is applied to the maximum entropy-based multi-threshold segmentation.Experimental results of image segmentation show that the proposed IBBO algorithm operates much faster than the exhaustive algorithm,and the optimization performance is better than that of the standard BBO algorithm and PSO algorithm.