Objective To explore the structure of college students’ optimism and develop a questionnaire. Methods The initial items of the questionnaire are formed by interview, open questionnaire and document retrieval. On the basis of forecast, 692 valid questionnaires are obtained from the subjects with the self-designed questionnaire. The life orientation questionnaire is used to test the validity of the criterion. Results The questionnaire on college students’ optimism contains 13 items, including two high-order factors: optimism and pessimism. Optimism includes optimistic expectation and optimistic explanatory style which pessimism factor includes pessimistic expectation and pessimistic explanatory style. The fitting indicators are better (X2/df = 3.45, GFI = 0.96, IFI = 0.95, NNFI = 0.93, CFI = 0.95 and RMSEA = 0.06), internal consistency reliability is between 0.61 and 0.74, and all sub-dimensions of the questionnaire are significantly correlated. The total scores of the questionnaire and four factors are positively correlated with the total scores of the life orientation questionnaire (0.74 ∼ 0.81). Conclusion The college students’ optimism is composed of four factors; the reliability and validity meet the requirements of psychometrics, and can be used in related research and practice. This study seemed to show that the CSOQ was a valid tool for measuring optimism among Chinese college students.