In order to significantly reduce the preparation and transportation costs of existing fracturing fluid，and realize online preparation of sand-carrying fluid，a new type of self-thickening proppant was prepared by attaching guanidine gum powder onto the surface of proppant particles. Performance evaluation and reservoir damage experiments of the self-thickening proppant were carried out under experimental conditions of high-temperature and high-salinity reservoir environment. The results showed that under conditions of 80℃，compared with injection water of SZ36-1 oilfield，injection water of Changqing oilfield，sewage of Daqing oilfield and fresh water of Daqing oilfield，guanidine gum solution prepared by injection water of Dagang oilfield with the highest salinity had the best gel forming effect，the highest apparent viscosity，the largest energy storage modulus and the strongest sand carrying capacity. When the sand ratio was greater than 30%，the suspension time of the self-thickening proppant was less than 20 s and the settling time was greater than 4 h. When the dosage of the self-thickening proppant was 0.03%—5.0%，the gel breaking time was 14—2.5 h. In the constant velocity experiment，with the increase of core permeability，the filtration loss increased gradually and the damage rate decreased gradually. In the constant pressure experiment，with the increase of the filtration pressure difference，the filtration amount and the injury rate gradually increased. The self-thickening proppant could meet the need of fracturing construction in high-temperature and high-salinity reservoir，and had a a broad application prospect.