The four-dimensional hyperchaos system is built by adding an additional state to the three-order Lü system. Some of its basic dynamical properties are studied briefly, such as the feature of equilibrium, the hyperchaos attractor, Lyapunov exponent and fractal dimension. An electronic circuit is designed to realize the four-dimensional hyperchaos system. Moreover, a novel analogue circuit is realized for the verification of various attractors.