Abstract: Passive thermal control system is very important for Nano-satellite′s temperature control and its working safety. The calculations of radiator surface area and heat insulation layer thickness are necessary for the design of passive thermal control system. A set of integrative design equations and algorithms were developed and described for the calculation of radiator surface area and heat insulation layer thickness through the heat transfer analysis of nano-satellite′s radiator surface and the multi layer heat insulation. The working flow of this integrative thermal design model and algorithm was also introduced. A sunsynchronous orbit Nano-satellites thermal design using this integrative model and algorithm was given as an example. The design example was analyzed and simulated. Result shows that the integrative design radiator surface and heat insulation layer can lead to a satisfactory thermal control effect, and a convenient design model and algorithm for nano-satellite′s passive thermal control system design is provided.