The embodiment of the invention provides an electronic map data mapping method and system. The method comprises the steps of obtaining a first node set and a first road section set corresponding to a first electronic map and a second node set and a second road section set corresponding to a second electronic map, if it is judged that a first feature endpoint and a second feature endpoint meet a first preset rule, the first endpoint road section adopting the first feature endpoint as the endpoint is mapped to the second endpoint road section adopting the second feature endpoint as the endpoint, a mapping result is obtained, and the mapping result is stored into a mapping result library and a to-be-extended road section library; if it is judged that the first road section and the second road section meet a second preset rule, the first road section is mapped to the second road section, a mapping result is obtained, and the mapping result is stored into the mapping result library and the to-be-extended road section library. The system is used for implementing the method. The electronic map data mapping efficiency is improved.