The interaction between soliton and sinusoidal wave in two weakly coupled long Josephson junctions is studied.Theoretical analysis reveals that the soliton may be embedded in Melnikov chaotic attractors and the Fiske-step-modes are implied in the boundedness condition of the system. Comparison between the chaotic soliton oscillators andsynchronized soliton oscillators shows that the former possesses greater maximal velocity and energy.