Abstract: In order to study the trajectory characteristics and influencing factors of liquid jets injected into low-speed air crossflow under different working conditions, the liquid jet breakup image is attained by the high speed camera, and the extraction method of trajectory characteristics of liquid jets injected into air crossflow is proposed, combined with image processing technology. Firstly, histogram equalization is used to enhance the gray-scale original image. Secondly, the optimal histogram entropy method (KSW entropy method) and traditional genetic algorithm are employed to achieve threshold segmentation. Finally, the Sobel operator and convex hull algorithm are served for extracting the jet edge contour, and obtaining the data point set of the jet trajectory. The results of trajectory extraction and fitting of typical jet breakup modes under different working conditions show that the proposed method can effectively extract the characteristics of the liquid jet fracture trajectory, and adapt to the track extraction of different liquid jet breakup modes under the action of low speed air crossflow. Besides, the empirical formula of jet breakup obtained by nonlinear fitting can predict the jet trajectory well.