Considering two-mode entangled coherent light field,one mode of the field is poured into the cavity and interacts resonantly with a cascade three-level atom. The squeezing and antibunching effects of the light field outside of the cavity are investigated,and Cauchy-Schwartz inequality is discussed. The influences of the selective atomic measurement and the intensity of the coherent field which interacts with atom on squeezing and antibunching effects of the field outside of the cavity are also discussed. The results obtained by numerical calculations show that quantum properties of the field outside of the cavity can be strengthened through selective atomic measurement and selecting the intensity of the coherent field which interacts with atom.