Atomic ensemble with strong nonlinear response provides a good platform to study the quantum properties of light. With the coherent interactions between fields and atomic system, the quantum nature of output fields which are quadrature variance and non-classical correlation will be essentially changed. In this talk, I would like to introduce our recent results which showthe generation of quantum squeezing in coherent population trapping atomic media. By adjusting three tunable parameters which are input light intensity, two-photon detuning, and optical density(OD), we can obtain the strong squeezing of more than 10 dB with high OD of 1,000 which isaccessible in experiments nowadays. On the other hand, I will mention our preliminary results for the quantum correlation between interacting fields after propagating through atomic ensemble. Our proposed scheme is very flexible and robust, and it has great potentials in applications of quantum optics and quantum information manipulation utilizing continuous variable.