A buffer memory management method, a memory control circuit unit and a memory storage device are provided. The buffer memory management method includes allocating a mapping table zone having a first zone and a second zone in the buffer memory, and temporarily storing a plurality of logical address-physical address mapping tables into the first zone and the second zone, and receiving a first write command which indicates writing first data into a first logical address. A first logical address-physical address mapping table to which the first logical address belongs is temporarily stored into a first buffer unit in the second zone. The method also includes updating the first logical address-physical address mapping table, moving the updated first logical address-physical address mapping table into a second buffer unit in the first zone, and marking the second buffer unit as a dirty status.