ObjectiveTo systematically evaluate the measurement properties of observational pain assessment scales for pediatric patients after surgery. MethodsThe PubMed, Embase, CINAHL, PsycArticles, and SinoMed databases were electronically searched to collect studies related to the objects from inception to April 13, 2024. Two reviewers independently screened literature, extracted data and assessed the risk of bias of the included studies. And the quality of measurement properties was rated using updated criteria for good measurement properties to determine recommendation levels. ResultsA total of 26 studies were finally included involving 12 observational pain assessment scales for pediatric patients after surgery. None reported measurement error or cross-cultural validity. The overall content validity of all 12 scales was evaluated by reviewers, with measurement properties rated as sufficient or inconsistent. For internal consistency, due to insufficient or uncertain content validity, the evidence quality was low. Eight scales calculated internal consistency, among which CHEOPS, CHIPPS, COMFORT, FLACC, and NCCPC-PV scales had sufficient measurement properties with evidence quality of low or above, receiving Grade A recommendations. ConclusionCompared with other scales, CHEOPS, CHIPPS, COMFORT, FLACC, and NCCPC-PV scales demonstrated good measurement property evaluation with acceptable evidence quality and can be recommended for use. Other scales still require further improvement in measurement property validation.