The fomula between the numbers of link of kinematic chain、the numbers of prismatic pair、the numbers of connecting rod for each unit、ring numbers of kinematic chain、and degree of freedom of mechanism with 3 degree of freedom has been introduced in this paper by means of method of numerical calculation,the configuration of kinematic chain with F=2 also has been introduced,and an example of systhesis of metamorphic mechanism for this kinematic chain have been listed the kinematic chain and its isomers for these mechanism with 3 degree of freedom have been studied by using the method of topological graph,the kinematic chains and its isomers and have been obtained for 28 types of mechanism which have 3 degree of freedom and its numbers of link is less than 10,this method is usful for type systhesis of metamorphic mechanism.