A method and device for checking validity of memory access are provided. A cache is established and initialization is performed; a total cache position index is calculated; when a program performs memory access, a graded cache unit is addressed according to the total cache position index, and it is determined whether address information of the memory block is able to be read from the graded cache unit; when the address information is able to be read, it is determined whether an instrumentation-based memory checking tool is needed for checking the validity of the current memory access; when the address information is not able to be read, the validity of the current memory access is checked by an instrumentation-based memory checking tool, and the address information of the memory block is filled into the graded cache unit when the current memory access is determined to be valid.