A nonlinear function of unified chaotic system, the family of switched unified chaotic system is generated which contains six kinds of subsystems. Each subsystem can be switched by changing systematic parameter values in parameter space, and these subsystems can be switched continuously from one to another via changing nonlinear function in state space. The features of these subsystems are analyzed in detail using Lyapunov exponent and bifurcation diagram. The division-time switching of unified chaotic system is realized based on digital signal processing (DSP).