The present invention relates to a system and method for desulfurization and denitrification integrated treatment and recycling of flue gas by using red mud, and belongs to the recycling and environmental protection technology field. The system includes a desulfurization spray tower, an ozone generator, a denitration spray tower, a slurry mixing tank, a slurry storage tank, a vacuum filter, an ammonia water neutralization tank, an aluminum hydroxide precipitation tank, an ammonia water tank, an aluminum hydroxide storage tank, a filter press, an ammonia distillation tower, a dephlegmator, a cooler, a concentrated ammonia water storage tank, a gypsum precipitation tank, and an anaerobic biochemical pool. In the present invention, red mud slurry is used for desulfurization and denitrification treatment of flue gas to remove SO2 and NO in the flue gas, so that SO2 and NO in the flue gas reach an emission standard.