In this paper,first,by using a new transformation,the variable coefficient KdV-MKdV equation is reduced to a third-order nonlinear ordinary differential equation (NODE),and then several exact soliton-solutions for the variable coefficient KdV-MKdV equatioin are obtained through considering this NODE.The method can be also used to solve other nonlinear equations,such as the variable coefficient KP equation,sine-Gordon equation and so on.