Abstract: Based on the series data of rainstorm and flood in Liaoning Province, this paper analyzes the weather system that affects rainstorms in Liaoning Province, expounds the characteristics of the main disasterous rainstorms in Liaoning Province since the founding of the People's Republic of China, analyzes and sums up the characteristics and laws of the cause mechanism of disaster causing rainstorms and floods, and provides technical support for the prevention and control of rainstorms and flood disasters in Liaoning Province.