Permeability enhancement , which is due to the sand produced from disturbed zone around wellbore, is the key mechanisms to improve the oil production rate in CHOPS. This has lead to the demand for the accurate predicting methodology to the amount of sand production. In this paper, a new integrated spread-erosion numerical model was developed, in which sand is produced from disturbed zone, and its dynamic performance depends on the spreading of wormhole which is determined by the pressure gradient between wormhole tips and reservoir. Also sand is fallen off from sand wall which is depends on the erosion parameter. Mechanisms case study shows that sanding will continue for a while even when the spread of disturbed zone is pause, as sand wall erosion is another source of sanding. Compare with wormhole lab testing data and sanding well monitoring data, sanding dynamic performance which is simulated by this new model is more reasonable and more reliable.