In order to resolve the problems that the most of mixer granulators had the stronger pertinence to materials or mixing equipments and granulators were separated, the horizontal double-rotary mixer granulator was developed based on the stirring and rubbing principles. The main structure and working principle were expounded. In the experiments, iron powder was used as the tracer to evaluate the mixing uniformity. The mixed deviation of the tester was 2.06%, the maximum mixing uniformity could attain 97.94%, when the mixed period was around 210 seconds. The mixed uniformity was evaluated by the curvature of linear regression curve with the particle diameter scatter diagram. When test time was between 50 and 1050 seconds, the granular range was from 3.89 to 18.79 millimeters. When mixed time was between 250 and 650 seconds, the slope of the linear regression curve was between 0.0644 and 0.1026. The mixing and granulating tests show that the horizontal double-rotary mixer granulator has strong adaptability to the pre-mixing powder, and has wider range of diameters of granule, higher mixing uniformity and granule uniformity, and shorter mixing cycle and granulating cycle.