The invention discloses a system for collecting, storing and recycling roof rainwater and a mounting method thereof. The system comprises a rainwater harvesting device, a vertical pipe rotational flow filtering device, a rainwater collecting device and a full-automatic water taking device. The rainwater harvesting device is arranged on a roof, and the vertical pipe rotational flow filtering device, the rainwater collecting device and the full-automatic water taking device are arranged on the earth surface. The mounting method comprises the following steps that (a) the mounting position is chosen; (b) the vertical pipe rotational flow filtering device is mounted; (c) the rainwater collecting device is mounted; (d) the full-automatic water taking device is mounted; (e) the rainwater harvesting device is mounted; and (f) the system for collecting, storing and recycling the roof rainwater is debugged. According to the system for collecting, storing and recycling the roof rainwater, rainwater early-stage flow abandoning and filtering are integrated, cost is low, the occupied space is small, mounting and maintenance are convenient, pipeline blocking is avoided, and the system can be used for a long period and is free of running managing and maintenance cost; and the roof rainwater can be filtered, collected, stored and used, and run off pollution of the rainwater can be effectively controlled, so that the environment is improved.