This study deals with numerical simulation of structure of covered yarns produced on a double covering machine. Four manufacturing parameters of covered yarns such as delivery speed of covered yarn, rotational speed of two hollow spindles, and core stretch ratio during wrapping were used to simulate coil length indices of both covering components. Coefficient of evenness of semi-manufactured product as a function of delivery speed of covered yarn and rotational speed of first hollow spindle was also computed. The influence of the above-mentioned process variables on the geometry of covering components was shown by means of analysis of corresponding relationships. To evaluate the intensity effect of each variable, the comparable partial differences of the proposed functions were computed. The computations were made for covered yarn structures composed of polyurethane elastomeric multifilament core wrapped with two viscose (CV) multifilament covering yarns.