A political party’s image is shaped through its concrete historical practices and major events. Over the course of a century of struggle, the Communist Party of China has forged an overall image of being great, glorious and correct through solid work and a strong sense of responsibility. Therefore, starting with an analysis of major events in the Party’s history is both an indispensable and appropriate approach to studying the image-building of the Communist Party of China. Event System Theory takes events as its basic unit, revealing their uniqueness, scope and intensity of influence from the dimensions of strength, time and space, and driving changes in entities, the formation of new behaviors and characteristics, or the triggering of subsequent events. This paper applies this theory to examine why the Xiangjiang Battle is a worthy research subject and uses it as an entry point to deeply analyze the Party’s image demonstrated in this process: upholding ideals and convictions through bloody struggles, adhering to the original aspiration of serving and benefiting the people, and daring to correct mistakes and conduct self-revolution. Introducing Event System Theory into the study of Party history can break through the single framework of traditional grand narratives, establish a connection between the micro-analysis of specific events and the overall construction of the Party’s image, and provide a micro-level yet solid historical basis for understanding “why the Communist Party of China is capable”. Thus, this study represents a valuable exploration from both the perspective of the Xiangjiang Battle case and the research on the Party’s image-building.