Abstract: In order to meet the requirement of real-time catching P-t curve in roof disaster monitoring system for disaster alert，rational pressure sensor was analyzed and selected.Intelligent sampling mode was put forward to obtain effective data and avoid resource waste of amounts of data by comparing setting threshold value.At the same time，recording data at fix moment was applied to solving the data lose problem from data mutation.Application showed that this intelligent sampling mode could make alert for roof disaster and instruct roof control.