Abstract: Recent studies suggest that noise could cause the occurrence of Duffing oscillator's phase-state transition, which is one of the most important reasons for the low system detection reliability and has been restricting the application of chaos theory in practical engineering. And hence one novel detection model containing nonlinear damping term is proposed in the paper based on generalized Van der Pol oscillator. And then it is proved feasible for weak signal detection by theoretical analyses. Compared to classical chaotic oscillators, the new model has stronger state robustness and noise immunity with equal complexity. Finally, Simulation results show that the application of the new model can reduce the impacts of noise on the phase-state transition and improve the detection reliability of weak signals.