Abstract: Open-source data is publicly available data released under specific open licensing agreements, which can be freely accessed and collaboratively developed by users. Distinct from public data, open-source data involves a weaker degree of rights transfer and uses an open source license to define the rights and obligations of all parties. Such licenses constitute contracts subject to a condition subsequent. During the creation of open-source data, open platforms may collect publicly available data within the legitimacy limits that satisfy the following four essential requirements. Between personal data subjects and open platforms, individuals’ right to opt out shall be fully respected; between non-personal data subjects and open platforms, the doctrine of transformative use shall be introduced to determine the legality of data sources. As for the reuse of open-source data, users may use open-source data for non-commercial purposes, but in commercial use scenarios, the scope of reuse defined in the open source agreement shall be strictly observed.