Abstract: The Lie symmetries and the conserved quantities of a variable mass nonholonomic system of non-Chetaev’s type are studied by introducing the infinitesimal transformations of groups in phase space.By using the invariance of the differential equations of motion under the infinitesmal transformations of groups, the determining equations and the restriction equations of the Lie symmetries of the system are established,and the structure equations and the conserved quantities are obtained.An example is given to illustrate the application of the result.