Abstract: The character of third-order dispersion in dispersion-manged solution system is studied.The influence of the third-order dispersion(TOD)on dispersion-managed soliton transmission system is investigated by means of variational method,and the evolution equations for the parameters of the optical Gaussian shaped pulse is derived.By simulation,we discussed the properties of the parameters under the influence of TOD.The nocuous influence and the necessarity of management of third-order dispersion is pointed out.