Abstract: The importance of the environment-control system for the large scale phased array radar radome is described in this paper. Then, with one large scale phased array radar as an example, the key points of its designing, including parametric demands,an executable scheme, contents, and illustrates the control strategy is introduced in detail. In addition, to achieve a delicate flow pattern inside the radome, a flow pattern is engineered with the aide of computational-fluid-dynamics numerical simulation, which is eventually experimentally validated to favor the uniformity of air temperature inside the radome. In conclusion, a practical scheme is provided for the design of the environment-control system for the radome-covered large scale radars.