The piercing mill parameters directly influence on the quality of pipes. In piercing mills, the process or setting parameters are the distance between rolls, rulers or guiding tools, mandrel extension, feed angle, rolling angle, etc. The geometrical parameters of deformation zone depend on the parameters of piercing mill. Non-optimal setting parameters of the piercing mill result in defects such as external and internal slabs. The accurate technological parameters of piercing process are needed to define the setting parameters of the piercing mill. There are numerous numbers of math models and methods to calculate the technological parameters, but all of them were developed for one specific type of piercing mill rollers. Taking into consideration all of the disadvantages of the existing math models, the new mathematical model has been developed to define technological parameters of piercing process. The main purpose of the math model is to calculate the technological parameters of piercing mill with barrel type, conical and cup-shaped rollers. The advantages of the math model comparison to the existing models are flexibility, a capability to define the parameters of all three types of the rollers and high accuracy. The model shows high accuracy even with high angle of rotation and the incline of the rollers up to 45°. The main idea of the model is to define the shortest distance between the rolling axes and the surface of rollers. The results have been evaluated using the CAD software program KOMPAS 3D for all three types of rollers of piercing mill. According to the results of comparison, the identities are equal to 100% for all three types of rollers.