Abstract: Based on the analysis of relevant process theory associated with the mandrel speed system of the retained mandrel pipe mill,the online mandrel speed model is studied and developed. With the said model,both the retained speed and the pre-piercing speed of the mandrel are solved via the linear programming method. The model comprehensively involves considerations of many a factors such as the mandrel wear,the product quality,and the rolling stability and rolling rhythm,etc. The model has been applied to a great number of newly-built domestic retained mandrel pipe mills. The feed backs of the applications demonstrate that the model features precise and reliable setting,and satisfactory operation effectiveness.