The present disclosure relates to a risk early warning method and system for hydrogen leakage, and relates to the field of hydrogen leakage. The method includes: obtaining ventilation information of a hydrogen-related area; carrying out grid division on a pipeline system of the hydrogen-related area to obtain a gridded pipeline system; determining a risk coefficient corresponding to each grid of the gridded pipeline system according to leakage sources of the pipeline system; determining a high-risk region by means of a jet cone model according to the risk coefficients; determining a medium-risk region, a low-risk region and a safe region according to the risk coefficients and the ventilation information; and carrying out risk early warning according to the high-risk region, the medium-risk region, the low-risk region and the safe region.