The invention discloses a manufacturing method for a surface totally-closed type inner multi-hole lightweight metal part. The manufacturing method is characterized by comprising the following steps that firstly, a geometric model is subjected to pretreatment; secondly, simplifying and repairing treatment is conducted on the model through an edge wall treatment manner, and a workpiece B is formed;thirdly, the workpiece B is divided into a body part and a support piece part; fourthly, after metal powder sintering is finished, surplus metal powder is poured out of a main component; fifthly, themain component is placed on a printing base table manufactured through five-axis high-temperature electric arc additional materials; sixthly, the five-axis high-temperature electric arc additional material manufacturing technology is adopted for conducting one or more layers of cladding on the B-P surface; and seventhly, a milling cutter is adopted for removing a closed plane P. The manufacturingmethod achieves the beneficial effects that the type of components are manufactured through the three-axis laser fusion selected area metal powder sintering 3D printing technology and five-axis high-temperature electric arc additional material manufacturing combined technology method, and the defect that an existing metal 3D printing technology manufactures the surface totally-closed type inner multi-hole lightweight metal part is overcome.