Abstract: In order to stow gob safely and economically，fly-ash transportation should be optimized.Under different transportation distances，by changing air input and transportation pressure，transportation efficiency，system export force and pressure lost were optimized to reach respective optimal value.Applying Electrical Capacitance Tomography(ECT) to simulating gas-solid flow，transportation rule of dilute phase and concentrated phase was obtained.Results showed that 200m was optimal transportation distance which could meet high efficiency，high pressure and low pressure lost.Transportation pressure，that is，pump start pressure influenced slightly.Dilute phase transportation would have higher efficiency.In practice，transportation distance should be controlled within 200m.