The effect of opto-mechanical parametric resonance (OMPR) described theoretically for the two-level system has important applications for a high-precision spectroscopy. A further investigation of this effect for the case of the three-level system that could be of interest from the experimental point of view is presented here. The main advantage of a method based on the OMPR is the possibility of using radio methods in optical spectroscopy. In this paper the calculation of the absorption coefficient of the three-level atom under OMPR conditions is presented.