In this paper we consider a new weak signal detection scheme which uses the sensitivity of chaos to the parameters under a certain status to realize weak signal detection- This scheme can effectively extract the weak sinusoidal signal from the strong colored noise background- We present a chaos-based signal detection approach, analyze the influence of noise to the system status in the chaos detection process- Simulation experiments show that the chaos detection system is very sensitive to weak signal and have strong constraint to any colored noise with zero mean value-