Under the condition of ensuring the high strength of the proppant, reducing the apparent density of the proppant as much as possible is the key to the development of shale gas clean water fracturing technology. In this work, low-grade bauxite and micro-SiO2 were used as the main raw materials, and water glass, nano-SiO2 and manganese oxide were used as auxiliary materials. The ultra-low density proppants were prepared by plasma dynamic sintering and later high-temperature sintering methods. The effects of different manganese oxide doping and different sintering time on phase composition, bulk density, apparent density and crushing rate at 69 MPa of proppants were discussed. And based on the classic PKN fracturing model, the settlement and migration of ultra-low density proppant in simulated fractures were studied. The results showed that an ultra-light proppant with an apparent density of 1.639 g/cm3 and a breakage ratio of 8.91% under 69 MPa was successfully prepared. The optimal manganese oxide doping content was 7.5wt%, and the optimal sintering temperature and sintering time were 950℃ and 2 h. Ultra-low density proppant migrated a longer distance in the horizontal direction than conventional proppants, and the distribution of proppant inside the fracture was relatively more uniform, which can meet the requirements of clean water fracturing for medium and deep oil wells.