A system and a method for cache coherence are provided. The system includes a memory apparatus, a detector, a plurality of access-consumers and a plurality of pass-gates. At least one of the access-consumers is a processor having a cache. When the processor replaces the first data in cache with the second data read from the memory apparatus, the process issues the read second data request first, followed by the write-back first data request. The detector provides a detecting signal when the processor issues the read second data request and cancels the provided detecting signal when the processor issues the write-back first data request. Each pass-gate decides whether to pass the third access request outputting from each corresponding access-consumer and transmit it to the memory apparatus according to the detecting signal respectively.