Abstract: Every bes t cho ice of several main factors affecting the crude purification of p ap ayaringspot virus(PRV)(including kinds of propagation host,organic clarification agent,dis pers io n agent,centrifugal force fo removing sediment before coneentrating thevirus,supereentrifugal foree for concentrating the virus)as reported detailedly in thispaper.Jelly melon(Cu cum is metuliferus)was found to be a better propagation hostthan the Zucchini Squash(Cucurb itapepo).A simple proeedure of one cycle of diffe-rent speed contrifugation and one cycle of Cs_2SO_4 continuous density gradientsupereentrifugation with sugar cushion was designed.The virus preparation showed atypical ultraviolet absorption curve for nucleoproteins,A260/A280=1. 68,the yield ofvirus was 2.56 mg/100 g of infected squash leaves and the virus preparation couldbe suitable for the further research on the serology and molecular biology of PRV.