The squeezing properties of the single-mode squeezing coherent light interacting with a three-level Ξ-scheme atomic Bose-Einstein condensate (BEC) are studied by means of quantum theory. The results show that the fluctuation of the light field can be squeezed periodically. The initial occupancy of the BEC atomic levels has great influence on the squeezing properties of light and the period of oscillation of the squeezing is relating to the circle frequency of the light. If all the BEC atoms are in the ground state at the initial moment, the squeezing of light appears regular periodicity. However, if some of the atoms are in the excited states at the initial moment, the distortion of the squeezing periodicity of light will emerges obviously, and this distortion is growing with the increase of the excited state’s occupancy. The occupancy of the excited states also influences the squeezing depth of light. The greater the occupancy of the excited states is, the deeper the squeezing.