Abstract: The subject of this research is the increase in the level of engineering design automation of CAD systems. The object of the research is gearings in mechanic engineering. The rationale of the research is caused by the need to make integrated solutions aimed at reducing the volume of work and time when modelling gearings in mechanic engineering and thus increasing efficiency of engineering design productivity. The author of the article focuses on difficult issues that can be faced in the process of modelling gearing profiles. In this research Pogrebnyak gives a description of the overall methods of parametric modeling in the process of desinging gearings in mechanic engineering. The author presents his method as a stage-by-stage sequence of actions consisting of six stages. The main result of the research is the method of parametric modelling of gearings using the direct programming method in the T-FLEX CAD 3D environment which allows to raise productivity of modelling, reduce time and efforts and increase the quality of design of gearings in mechanic engineering.