Introduction The evolution of computed tomography (CT) findings in patients with mild coronavirus disease 2019 (COVID-19) pneumonia has not been described in detail. A large-scale longitudinal study is urgently required. Methods We analyzed 606 CT scans of 182 patients. The dynamic evolution of CT scores was evaluated using two staging methods: one was divided into 10 periods based on decile intervals, and the other was one stage per week. Moreover, the latter was used to evaluate the dynamic evolution of imaging performance. A published severity scoring system was used to compare findings of the two methods. Results In the dynamic evolution of 10 stages, the total lesion CT score peaked during stage 3 (9–11 days) and stage 6 (17–18 days), with scores = 7.19 ± 3.66 and 8.00 ± 4.57, respectively. The consolidation score peaked during stage 6 (17–18 days; score = 2.72 ± 3.07). In contrast, when a 1-week interval was used and time was divided into five stages, the total lesion score peaked during week 3 (score = 7.3 ± 4.15). The consolidation score peaked during week 2 (score = 2.54 ± 3.25). The predominant CT patterns differed significantly during each stage (P