Abstract: A theoretical model for the productivity estimate and management system (PEMS) of engineering items is proposed based on the concept of productivity management with its operational mechanism described. Meanwhile, combined with the practice of engineering items, a practical model for the measure, prediction and improvement (MPI) of productivity is built under the guidance of the proposed theoretical model. The analysis of the application of the MPI model into an engineering example shows that the model is characterized by simplicity and effectiveness, and be suitable for the spot application of engineering items. The calculation result provides a basis for contractors to recognize and analyze the construction claims for losses resulted from the productivity decrease, and to control and improve the productivity.