The invention provides a vacuum lightweight well-point dewatering method, which comprises the following steps of: arranging at least one row of working face advanced vacuum dewatering pipes according to a certain annular interval within a certain angle range of working face vault; excavating an upper step, and arranging at least one row of first vacuum dewatering pipes at a certain distance under the arch foot of the upper step; and excavating an intermediate step, and arranging at least one row of first vacuum dewatering pipes at a certain distance under the arch foot of the intermediate step. The dewatering pipes are arranged according to an excavating working method adopted in tunneling, therefore the method disclosed by the invention has the advantages of simple process, convenience for construction and operation, low energy consumption, low construction cost and good dewatering effect; and the construction equipment is simple to assort, the arrangement of large-scale equipment when other dewatering methods are adopted is reduced, and the construction equipment has the advantages of simpleness in installation, strong operability and convenience for maintenance.