The invention discloses a powder metallurgy mixing device. The powder metallurgy mixing device comprises a hollow cylinder, wherein two side walls of the cylinder are fixedly connected with a solid rod with an axis being collinear with the axis of the cylinder. The powder metallurgy mixing device is characterized by also comprising a waist-shaped through hole which penetrates through the side walls of the cylinder and the solid rod, wherein a waist-shaped sliding block which can only slide in the through hole is arranged in the waist-shaped through hole, and the sliding block is also connected with a transmission shaft connected with a rotating device. The transmission shaft can drive the cylinder to rotate through the sliding block, and as the sliding block can slide in the through hole, in a rotation process of the sliding block, the cylinder does lifting movements under the action of gravity, so that materials can be mixed more sufficiently.