The invention relates to a portable foldable four-rotor aircraft which comprises a main frame of an aircraft body, a cantilever and an undercarriage, wherein the cantilever is fixed on the main frame of the aircraft body in a rotating form through a first fixing shaft and the undercarriage is fixed on the cantilever in a rotating form through a third fixing shaft. The portable foldable four-rotor aircraft has the advantages of compact structure, small size, quick mounting and detaching, easiness in maintenance and low cost, and the assembling efficiency can be improved to the maximum extent.