A new four-dimensional continuous-time autonomous hyperchaotic system is proposed in this paper，which is built by adding a nonlinear controller to a three-dimensional continuous-time autonomous chaotic system. The hyperchaotic system is analyzed by studying the Lyapunov exponent spectrum and bifurcation diagram. The system will take on periodic and complex periodic，chaotic and hyperchaotic behaviors with change of the parameter. Also，an electronic circuit is designed and realized，the experimental results verify the conclusions.