Abstract: Taking the solid-liquid phase flow pipeline transport technology of deep-sea mining as the applied background，the law of resistance loss changing in horizontal pipeline under conditions of different particle size，volume and concentration，and conveying velocity were investigated by building the simulation system of hydraulic pipeline transport.The results showed that the higher volume concentration or the greater transportation velocity is，the more resistance loss would be.The relationships between the resistance loss and each parameter are as following.If other conditions stay the same，there is the exponential relationship between the resistance loss and the concentration or the velocity.Particle's movement has a certain effect on the rate of resistance changing.Based on the experimental data and the theoretical analysis，the formula for calculating the resistance loss was proposed.

Key words: Coarse particles, Horizontal pipeline, Transport, Friction loss