Abstract: In the modern drilling operation， the separation and recycle of weighting-materials become more and more important.Through theoretical calculation and experimental analysis and according to the graphic processing and optimal algorithm，the distribution curves of solid-phase recycled rate and granularity distribution are obtained.The determination of the relation between solid-phase granularity distribution and recycled rate is favorable to research the solid-liquid-phase separation mechanism of centrifuge，which provides credible basis for recovering weighting-material and saving resource.

Key words: weighting-material, horizontal decanter centrifuge, solid-phase recycled rate, separation granularity, optimal design