Objective To explore the latent classes of illness uncertainty in outpatients with pulmonary nodules, and to analyze influencing factors of each latent class. Methods A total of 487 outpatients with pulmonary nodules were selected using convenient sampling, then they were investigated by utilizing a general information questionnaire, the Mishel Uncertainty in Illness Scale, the Perceived Social Support Scale, the Simplified Coping Style Questionnaire and the Brief Illness Perception Questionnaire.The latent profile analysis was conducted to identify latent classes of participants′ illness uncertainty, and predictors of each class were explored by conducting univariate analysis, ANOVA and logistic regression analysis. Results Three latent classes of the participants′ illness uncertainty were identified, namely low level complexity group (28.3%), medium level unpredictability group (35.5%), and high level uncertainty combined with deficient information group (36.2%).The results of logistic regression analysis showed that, the patients with high social support, active coping, 40-59 years old, and have quitted smoking were more likely to develop into the low level complexity group, while the patients with negative coping were prone to be divided into the other two groups; in addition, the divorced/widowed, self funded patients and those with ground glass pulmonary nodules were inclined to be classified into the high level uncertainty combined with deficient information group. Conclusion The outpatients with pulmonary nodule have significantly different classification characteristics of illness uncertainty, and targeted and precise emotion management should be implemented based on their characteristics of different categories in the future.