Method, system, bus arbitration device for accessing a memory are described. According to one embodiment, priorities of N function modules accessing the memory are compared to obtain location information of a function module with the highest priority. A bus of the function modules accessing the memory is switched to the function module with the highest priority by performing logic operation on the location information and bus information of each function module. Further, a bus arbitration device including a priority arbitration unit and a bus switching unit is described.