Abstract：Field investigation was conducted to study the occurrence dynamics of southern rust in fresh corn production area in Guangzhou．In addition，hundred-grain weight was used as an important index to analyze the correlation between southern rust damage degree and fresh corn yield．Result showed that southern rust could occurre all year round during fresh corn growing period．The 2 occurrence peaks were in July and November．Southern rust damage could significantly reduce the hundred-grain weight of fresh corn．The regression analysis indicated that there was a significant negative correlation between hundred-grain weight of fresh corn and disease severity of southern rust．The regression equation was y=-0.031 x + 31.924．The hundred-grain weight would reduce by about 0.3 g，when southern rust severity increased by 10%．