A testing device for memory includes a memory array and a test apparatus. The test apparatus includes a controller and a pattern generator. The pattern generator generates a background data, a first pattern data, and a second pattern data. The controller sets up the background data to a to-be-tested memory sub-array of the memory sub-arrays, performs a first memory test operation with the to-be-tested memory sub-array according to the first pattern data for detecting an occurrence of a hardware failure of the to-be-tested memory sub-array is occurred during the first memory test operation. The controller performs a second memory test operation with the to-be-tested memory sub-array according to the second pattern data for detecting the occurrence of the hardware failure of the to-be-tested memory sub-array during the second memory test operation in response to the hardware failure of the to-be-tested memory sub-array is not occurred during the first memory test operation.