Nowadays free-radical-copolymerizatrion is one of the major industrial ways of copolymer synthesis [1]. It is used to produce a vast variety of copolymers. However, this method has certain shortcomings that may lead to deterioration of physico-chemical properties of the products obtained. Recently a new method of “living” free-radical copolymerization was developed, which permits to overcome these difficulties [2]. When synthesizing new copolymers it is necessary to be able to predict their physico-chemical properties. For the products of free-radical copolymerization this problem was solved theoretically [1] and on the basis of this general theory the software modeling tool was developed [3] that permits one to calculate various properties of the copolymers synthesized. Recently similar general theory [4] was put forward enabling one to describe chemical structure of the products of “living” free-radical copolymerization. In this work we present the software modeling tool which makes possible the calculation of some physico-chemical properties of such copolymers. In particular, it enables calculation of spinodal of the system. 1. S. I. Kuchanov, Methods of Kinetic Calculations in Polymer Chemistry (in Russian), Khimia, Moscow, 1978 2. K. Matyjaszewski, in Controlled Radical Polymerization, edited by K. Matyjaszewski, ACS Symp. Ser., v. 685, ch. 1, pp 2-30, 1998 3. http://www.copolymerization.da.ru 4. S. I. Kuchanov, T. V. Zharnikov, European Physical Journal ser. E, v.7, p183, 2002