Through the analysis of monitoring data in cotton growing period,change in soil salinity with different irrigation norms in the different conditions of drip irrigation are studied.Results show that the quantity of irrigated water has significant influences on soil salinity.The soil salinity after irrigation is significantly lower than the initial soil salinity and the more water,the more obvious effect of washing salt is.The suppression salt treatment of seven-day irrigating cycle is better than 3.5-day irrigating cycle.Soil salinity is increased with emitter distance.The decreased trend of soil salinity is significant under emitter and the salt accumulation has no change within 50cm from emitter in horizontal direction.Through the quantitative analysis of soil salinity around the main root of cotton,the optimal mode of salt washing is the seven-day irrigation cycle with the 3900-4500m³/hm² of irrigation norm.