Provided is a collision prevention system of a multi-master including: a plurality of external modules; and an integrated device. The integrated device includes: a plurality of interfaces connected respectively to the plurality of external modules and respectively controlled by corresponding external modules; a plurality of internal modules; a plurality of dedicated buffers connected respectively to the plurality of interfaces and the plurality of internal modules; and a common block connected to the plurality of dedicated buffers and controlled by the plurality of interfaces and the plurality of internal modules. The plurality of dedicated buffers includes a GBU and a plurality of LBUs. The GBU and the plurality of LBUs are connected to two neighboring GBUs and a plurality of LBUs to form a ring communication topology, which transmits ring communication data in one direction. The common block is connected to the ring communication topology through the GBU.