This paper further investigates a non-autonomous unified chaotic system with continuous periodic switch found in [Lu J, Wu X. A unified chaotic system with continuous periodic switch. Chaos, Solitons & Fractals 2004;20:245-51], which is another different realization for the unified chaotic system developed in [Lu J, Chen G, Cheng D, Celikovsky S. Bridge the gap between the Lorenz system and the Chen system, lilt J Bifurcat Chaos 2002; 12:2917-26]. Hyperchaofic behavior is discovered within some system parameter range, which has not yet been reported before. The detailed behaviors of this system are not only dernonstrated by computer simulations but also verified with Lyapunov exponents spectrum, bifurcation analysis and Poincdre maps. (c) 2005 Elsevier Ltd. All rights reserved.