The present invention provides an information traceability method and system based on a blockchain. The method includes: receiving a traceability request, where the traceability request includes a type label, a time label, and a content label; accessing information path data pre-stored in the blockchain based on the type label to obtain target path data, where the target path data is single-source path data or multi-source path data; determining a corresponding primary data set based on the time label, where the target path data includes a plurality of primary data sets; determining a corresponding secondary data set based on the content label, where the primary data set includes at least one secondary data set; and extracting path information from the secondary data set, and obtaining at least one information source based on the path information. In the technical solution of the present invention, an information source can be quickly located based on different labels in the traceability request during information traceability, which reduces a volume of data traversed during searching for the information source, saves a time for searching for the information source, and has relatively high efficiency.