Based on surrogate data hypothesis testing, this paper presented an improved nonlinear test algorithm for deterministic chaotic signals, which is applied to the analysis of abnormal rhythm electrocardiosignals. It is pointed out that ventricular tachycardia(VT) and ventricular fibrillation(VF) are complex nonlinear chaotic signals, which was proved different from stochastic signal. On the basis of qualitative signal analysis and nonlinear dynamics, the authors forwarded a new definition of complexity rate and proposed relative detection methods for the quantitative analysis of VT and VF. The results indicated that the qualitative analysis and quantitative analysis of VT and VF can give objective and creditable results.