In order to study the solid-liquid twophase flow field and the hydrotransport characteristics of variable concentration in vortex pump, the basic principle and characteristics of solid-liquid twophase flow in vortex pump were summarized analytically and the characteristics of solid-liquid two phase flow were discussed based on the following aspects: energy exchange between solid and liquid, the round flow of particles and the interference between particles. The performance test of clean water and rapeseed volume fraction of CV=6% and CV=10% hydrotransport were conducted on a selfbuilt vortex pump (32WB8-12). Through the experiments, performance curves, such as qv-H, qv-P, qv-η and qv-NPSHc, were obtained. Based on the mixture multiphase flow model and the modified k-ε twoequation turbulent model, the interior twophase flow field of rapeseed liquid hydrotransport under the clear water optimal condition flow qv=9.31m3/h was numerically simulated by using SIMPLE algorithm. The pressure, velocity and sandy volume fraction, distributed on three cross sections of the vortex pump, were obtained through the numerical modeling. Meanwhile, the simulation results also showed that the rapeseed particles were mainly gathered at axial vortex center in the impeller and the annular district confront impeller in the chamber as well as around the blade inlet, and the accuracy of the numerical simulation results was verified by comparing between simulation and experiment. By comprehensive analysis, the relationship between performance and parameters of the internal flow was explained, the variable concentration similar conversion of NPSH and improvement measures for optimizing the design of the twophase flow pump were proposed.