The agglomeration behaviour of Mo powder, especially fine Mo powder, has been a major concern. The degree of powder agglomeration is directly related to the uniformity of Mo and its alloy powder mixtures and related target materials. This study mainly focuses on how to efficiently reduce the soft agglomerates behaviour of Mo powder. Analysis of the micromorphology and median particle size (D50) of modified Mo powder showed that the soft agglomerates behaviour of Mo powder can be divided into three stages: drawing, gathering, and sticking. Modification of the Mo powder surface by the polymer surfactant PVP-K30 can effectively prevent the agglomeration of the Mo powder. Additionally, the surface hydroxyl groups of the Mo powder disappeared, the agglomerate factor decreased from 13.02 to 5.04, and the flowability of the Mo powder was significantly improved. This is important for improving the grain uniformity and application performance of Mo target materials synthesized from Mo powder.