The invention relates to a multiphase flow test flume system which comprises a main body, a clear water circulating system, a muddy water circulating system, a water inlet system, a control system and a water outlet switching system, wherein a support and a jack are arranged at the bottom of the main body and are fixed on the ground by supporting hinges for adjusting the width and the gradient of a flume, and the water inlet system comprises a sampling discharge outlet, a manual valve, a flowmeter and an electromagnetic valve and is connected with the top end of the main body; the control system is arranged at one side of the top end of the main body for controlling all switches, and the water outlet switching system is arranged at one outer side end of a water outlet of the main body and is connected with a clear underground water pool in the clear water circulating system and a muddy underground water pool in the muddy water circulating system. Due to the clear water circulating system and the muddy water circulating system which are independent, the invention reduces test water consumption and test cost and conveniently recycles and treats polluted water samples, and a clear water / muddy water switching device of a water outlet system is easily designed and conveniently operated so as to effectively solve the switching problem among different circulating systems.