The invention discloses an additive manufacturing device composite powder compacting and spreading device and method. The powder spreading device comprises a pressure powder spreading machine and a vibration system, wherein the pressure powder spreading machine is provided with a coating surface with a certain inclined angle and used for spreading a powder material, and the vibration system is used for vibrating and compacting the spread powder material. According to the powder spreading device, due to the fact that the pressure powder spreading machine is provided with the coating surface with the certain inclined angle, in the powder spreading process, after loose powder enters the included angle formed between the coating surface and a powder spreading plane, the heated loose powder is mutually extruded through the gradually-decreasing space, and then gaps between the powder become smaller; the vibration system vibrates and pressurizes the extruded powder, distribution arrangement of the gaps between the extruded powder is stabilized, namely, rebound of the spread powder is reduced, the powder material is elastically deformed and then the flat-spread powder is compacted, so that compactness of three-dimensional forming products is improved, and mechanical performance of the three-dimensional forming products is further improved.