With function expansion method,we obtain several types of solitary wave solutions of modified coupled KdV (cKdV) equations,including kink-bell-like soliton,double kinks soliton,double bells soliton and double kinks-double bells soliton.These solitary wave solutions are reduced to kink or bell-like solitons solution under different limitations.We also investigate numerically stability of solitary wave solutions.It indicates that the system of modified cKdV equations has both stable solitary wave solutions and unstable solitary wave solutions.

The amplitude of particle velocity of one soliton in Toda lattice is given. The paper also provides the dependence of the maximum velocity in the interacting process of both solitions on the initial amplitude prior to collision.