The invention relates to a culture wastewater efficient degrading and denitrifying treatment system and a treatment method thereof. The system comprises, sequentially connected, an equalizing basin, a sand precipitation basin, a feeding basin, an anaerobic reactor, a preoxidation-nitrosation integration basin, an anaerobic ammoxidation reactor and an outlet water return basin, the anaerobic reactor is an anaerobic internal circulation reactor, wastewater flows through an external circular basin cavity and then enters an internal circular basin cavity, the anaerobic ammoxidation reactor is an upflow anaerobic packed tower, culture wastewater goes through above structures to sequentially undergo purifying reactions comprising hydrolysis, sand removal, anaerobic treatment, nitrosation and anaerobic ammoxidation, and harmful pollutants can be efficiently removed through multi-grade degrading treatment. The method combines an anaerobic process with an anaerobic ammoxidation process, and allows COD to be removed through the anaerobic process and nitrogen to be removed through the anaerobic ammoxidation process, so efficient removal of high-concentration pollution components in the culture wastewater is realized, and the method is simple to operate and stably runs.