Based on conventional triaxial compression test,as the water content and the number of reinforcement layer of geogrid-reinforced clay changed the change laws of parameters of Duncan-Chang mode which is widely used in the numerical analysis of geotechnical engineering were studied.In the triaxial test,the water content was set as 17.5%,20%,22.5% and 25%,and the number of reinforcement layer was set as 0,1 and 2.The test results and analyses showed that the parameters of Duncan-Chang model varied in certain rules with the water content and number of reinforcement layer,especially,the value of the c,φ,K,nandDevidently varied with the water content.It can be considered that water content is the most important factor to cause the change of the parameters of Duncan-Chang model for geogrid-reinforced clay,the embedding of geogrid into clay can increase the value of c,φ,K,nandD of clay.It is evident that the strength of clay with geo-grid can be increased.