Objective To construct the visualization training platform based on a multimodal standardized dataset for pain assessment in critically ill children and evaluate the usability of the platform.Methods Utilizing deliberate practice as the theoretical guide, a visualization training platform was developed for pain assessment in pediatric critical care, employing the multimodal standardized dataset.Two major modules were available for the platform:the learning materials module and the pain assessment training mo-dule, comprising 2 major chapters, 9 subsections and 104 cases.A purposive sampling method was used to select 14 pediatric nurses specialized in critical care for preliminary application of the platform.The usability of the platform was evaluated using the System Usability Scale (SUS) and semi-structured interviews.Results All 14 participants completed the theoretical learning of 2 major chapters with 9 subsections, as well as 4 exercises of pain assessment on the platform.The overall SUS usability score of the platform was 73.50±9.94.Four themes were identified for qualitative interviews:better learning experience provided by the platform, multidimensional benefits from its usage, willingness of use influenced by platform accessibility and burden of use, platform usability in need of further improvement.Conclusion The visualization training platform based on a multimodal standardized dataset for pain assessment in critically ill children demonstrated good usability.However, further improvements are still needed in terms of accessibility, intuitiveness, and functionality to ensure an even better training experience and effectiveness.