Abstract: A testing system for measuring loss of soil particles with different particle sizes in a water inrush process includes: a vibration screening apparatus; a water collecting apparatus for collecting the mass of water and transmitting the water to a collecting and calculating apparatus; a conveying apparatus for conveying screened soil particles to a weighing apparatus; a weighing apparatus used for weighing the screened soil particles and transmitting the measured weight of the screened soil particles to the collecting and calculating apparatus; and a collecting and calculating apparatus used for controlling the operation of the testing system, inputting parameters and calculating data. The condition of particle loss in a simulated tunnel water inrush process can be automatically measured in real time, providing a basis for researching the influence caused by the particle sizes of fillings in the water inrush process of the tunnel to water inrush.