Abstract: The fundamental characteristics of soliton and chaos in nonlinear equation are completely different.But all nonlinear equations with a soliton solution may derive chaos.While only some equations with a chaos solution have a soliton solution.The conditions of the two solutions are different.When some parameters are certain constants,the soliton is derived;while these parameters vary in a certain region,the bifurcation-chaos appears.It connects a chaotic control probably.The double solutions correspond possibly to the wave-particle duality in quantum theory,and connect the double solution theory of the nonlinear wave mechanics.Some nonlinear equations possess soliton and chaos,whose new meanings are discussed briefly in mathematics,physics and particle theory.