Abstract: With the deepening of research on the relationship between environment and health, environmental health risk assessment is increasingly reliant on multi-source data. This paper systematically reviews the types and characteristics of multi-source data in environmental health risk assessment and analyzes their application value in exposure modeling, health effect identification, and risk prediction. Data quality assessment and usability evaluation run throughout the entire process of multi-source data integration and are key to ensuring the accuracy, representativeness, and consistency of the integrated data. The paper summarizes key indicators and international practices of data usability evaluation, further consolidating advanced experiences in data quality standard construction and integration mechanisms both in China and in other countries. Based on the current situation in China, the study proposes improvement pathways and policy recommendations to advance the construction of multi-source data integration mechanisms and quality control systems, with the aim of enhancing the scientific rigor and decision-making supporting capacity of environmental health risk assessment in China.