Study Design. A prospective study. Objective. The aim of this study was to develop the simplified Chinese version of Pain Self-efficacy Questionnaire (PSEQ) (SC-PESQ) and PSEQ-2 (SC-PSEQ-2), and evaluate the psychometric properties of the two questionnaires in patients with nonspecific low back pain. Summary of Background Data. PSEQ has been cross-culturally adapted into many languages with excellent reliability and validity. Recently, the short form of PSEQ-2 was developed and exhibited satisfactory psychometric properties. However, PSEQ and PSEQ-2 has not been translated or validated in mainland China. Methods. The original version of PSEQ and PSEQ-2 was linguistically translated and adapted to formulate the simplified Chinese version, which was then administrated by 219 patients with low back pain, along with a set of self-report health-related instruments. Statistical analysis was performed to evaluate the psychometric properties of the SC-PESQ and SC-PSEQ-2. Results. Two hundred nineteen patients with nonspecific low back pain were enlisted into the analysis. The SC-PSEQ and SC-PSEQ-2 had been determined excellent internal consistency (Cronbach alpha, 0.95 and 0.83), test-retest reliability (overall ICC, 0.91 and 0.88), and sound construct validity, which were supported by moderately strong association with the criterion measures, respectively. In addition, exploratory and confirmatory factor analysis have found and confirmed one-factor solution in SC-PSEQ as hypothesized. Conclusion. The SC-PESQ and SC-PSEQ-2 showed satisfactory psychometric properties in Chinese population with low back pain, and could be safely utilized to evaluating the self-efficacy in clinical and research setting. Level of Evidence: 4