For the difficulty of recognizing infrared small targets in sky backgrounds and its low recognition reliability,an improved method based on the unfair D-S evidential theory for small target recognition is presented combined with the previous methods.To improve the recognition confidence degree,the velocity and gray information of small targets is regarded as the major evidence,and the track information of the targets is treated as the supplement evidence.The proposed algorithm firstly recognizes the small target by using the velocity and gray information.If the targets cannot be recognized only by using the velocity and gray information,the target track information should be added into the fusion evidences to complete the fusion by the unfair D-S evidence method.If the added target track information can strongly support the decision of target velocity or target gray,the proposed algorithm can evidently improve the recognition reliability of infrared small targets in sky backgrounds.The simulation results show that recognition confidence degrees are raised by 125% without adding new sensors.