Abstract: In order to study the effect of proppant density on slick water prop-carrying capacity, a large visual-panel fracture simulation system was designed, making the dynamic settlement and sand bank state of proppant visible in fractures. This apparatus was used to study the slick water prop-carrying capacity under various proppant densities and the settlement-migration law of proppant in fractures. The results shows that, with the extension of experiment time, the height of sand bank increases gradually but the rate reduces; with the decrease of proppant density, the sand bank becomes gentle and its height reduces (the peak moves into deep fractures and the bank moves more quickly into the deep fractures, so more proppant settles in deep fractures); the increase of proppant density affects the settlement speed greatly but poses little effect on horizontal migration speed. This research provides references for proppant on the settlement-migration dynamic study and optimal selection.