Prefect fore-separation technology is the precondition and key to realize garbage synthesis treatment and increase resource utilization ratio. To the lower purity quotient and efficiency of plastic and paper separation, main factors influencing performance of horizontal flow separation are analyzed in detail, and reasonable processing and design parameter are studyed in this paper. Horizontal flow separator of urban garbage that structure is reasonable and parameter can be adjusted is designed. Technology reference and support is provided to production of urban garbage treatment factory.