Antiangiogenic therapy is the anti-tumor treatment, that leads to the cessation of blood vessels formation and subsequent nutrient deprivation of the tumor. One of its frequently occurring effects is the transient improvement of tumor oxygenation, which lasts several days and leads to increased efficiency of successive exposure to radiation. It is followed by an escalation of hypoxia, and therefore the addition of antiangiogenic therapy to the whole course of fractionated radiotherapy has an ambiguous effect. Previously we have developed a mathematical model of such combined anti-tumor treatment. Herein we present an algorithm of optimization of radiotherapy fractionation, which aim is to find the most optimal distribution of irradiation doses in order to increase the efficiency of such combined treatment. We demonstrate an example of its work and discuss its further application.