The invention relates to an experiment system for low impact development facility water quality simulation. The experiment system comprises an LID facility water quality simulation unit, an artificial rainfall control unit and a sample collection unit, wherein the LID facility water quality simulation unit comprises an experiment box (12) and an LID facility, the experiment box (12) and the LID facility are arranged in a side-by-side manner, the top portion of the experiment box (12) is opening, the LID facility is arranged inside the experiment box (12) and is communicated to the sample collection unit, the artificial rainfall control unit comprises a mixing assembly, a water supply assembly and a spraying assembly, the mixing assembly, the water supply assembly and the spraying assembly are sequentially connected through water conducting pipes (4), and the spraying assembly is arranged above the experiment box (12), and is arranged opposite to the LID facility. Compared with the experiment system in the prior art, the experiment system of the present invention has advantages of simple structure, convenient operation, economy and practicality, and is suitable for the low impact development facility water quality simulation research in the room, and further has the water amount simulation function.