A drained water recovery system of a process device and recovering method thereof is provided. The recovering method includes using a conductivity meter to measure the conductivity of the drained water so that the drained water with different degrees of conductivity are channeled to different pipelines. Furthermore, another conductivity meter and a total organic carbon analyzer together with an interim tank liquid level controller sorts out the recovered water. Thereafter, according to the properties of the recovered water, the drained water is re-used to improve recycling efficiency.