Abstract: Ambidextrous strategy plays an important role in the process of catch-up, but we still know little about how to choose the approach to ambidextrous strategy in different windows of opportunity. Through HAILUN's longitudinal case study from 1986 to 2019, it is found that latecomers usually adopt exploitative strategy when opportunities are single and relatively certain. When the opportunity is single but the uncertainty is large, latecomers usually adopt explorative strategy. When latecomers are faced with multiple and uncertain opportunity and have a high absorptive capacity, ambidextrous strategy becomes particularly important. Longitudinally, in the process from initial catch-up to beyond catch-up, the strategy of latecomers has evolved from "sequential ambidexterity" to "simultaneous ambidexterity". The conclusion of this paper not only enriches the theory of catch-up, but also complements the research on the antecedents of ambidextrous mode.