A semiconductor memory apparatus and a testing method thereof are provided. The semiconductor memory apparatus includes a memory chip and a memory controller. The memory controller is configured to detect an initial test voltage of a target memory cell corresponding to a tailing bit in a main array of the memory chip. After the memory chip is idle for a first time, the memory controller detects a first test voltage of the target memory cell and compares it with a current comparison voltage to determine whether a first stage test is passed. In a case of passing the first stage test, after the memory chip is idle for a second time, the memory controller detects a second test voltage of the target memory cell and compares it with the current comparison voltage to determine whether a second stage test is passed. The comparison voltage is dynamically updated in response to the time the memory chip is idle.