Objective: By comparing the psychometric properties of the Short Form 36 (version 1, SF-36) and the Short Form 12 (version 1, SF-12), we supply evidence for the selection of instruments measuring the quality of life (QOL) and decision-making processes of adolescents in China. Methods: Stratified cluster random sampling was adopted, and the SF-36 was administered to assess QOL. The Pearson correlation coefficient was used to show correlation. Cronbach’s alpha and construct reliability (CR) were used to evaluate the reliability of SF-36 and SF-12, while criterion validity and average variance extracted (AVE, convergence validity) were used to evaluate validity. Confirmatory factor analysis was used to calculate the load factor for each item, then to obtain the CR and AVE. The Semejima grade response model (logistic two-parameter module) in item response theory was used to estimate item discrimination, item difficulty, and item average information for each item. Results: 19,428 samples were included in the study. The mean age of respondents was 14.78 years (SD = 1.77). High correlations between the corresponding domains and components of both scales were found. Reliability of each domain of the SF-36 was better than for the corresponding domain of SF-12. The domains of PF, RP, BP, and GH in SF-36 had good construct reliability (CR > 0.6). The criterion validities of SF-36 were a little higher in some corresponding dimensions, except for PCS. The convergence validities of SF-12 were higher than SF-36 in PF, RP, BP, and PCS. The items of BP, SF, RP, and VT in SF-12 had acceptable discrimination of items that were higher than in SF-36. The items’ average amounts of information of BP, VT, SF, RE, and MH in SF-36 and SF-12 were poor. Conclusion: Two component measurements of the SF-12 (PCS and MCS) appeared to perform at least as well as the SF-36 in cross-sectional settings in adolescence, but the reliability and validity of 8 domains of the SF-36 were better than those of SF-12. Some domains, for instance SF and BP, were not suitable for adolescents or need no further study.