The invention discloses a rainwater collection system, which comprises a tank, a rainwater filtering device, at least one shallow cage way and at least one deep cage way, wherein a water inlet, an overflow port and a drainage port are formed in the water tank; rainwater from external side can be guided into the water tank through the water inlet; the overflow port is opened at normal times, and rainwater, which achieves a preset water level in the water tank, can overflow out of the water tank; the drainage port is closed at normal times, and most rainwater in the water tank is discharged when the drainage port is opened; by virtue of the rainwater filtering device, the rainwater is filtered and then the filtered rainwater is guided into the water tank from the water inlet; the shallow cage way is arranged at a relatively shallow part underground and is connected to the overflow port, so that the rainwater, which flows out of the overflow port, is guided to a relatively far place; and the deep cage way is arranged at relatively deep part underground and is connected to the drainage port, so that the rainwater, which flows out of the drainage port, is guided to a relatively far place; therefore, with the application of the structure, the rainwater can be collected and stored and the rainwater can penetrate into a predetermined part, so that utilization rate of a water resource is improved; and the rainwater collection system, which is applicable to various topographies and land forms, is practical and convenient.