A method for memory testing implemented on an embedded system, the method comprising steps of loading a booting program when the embedded system is booted; activating a RAM of the embedded system by the booting program; duplicating the booting program itself and writing the duplicated booting program into a first section of the RAM by the booting program; downloading a testing program from an on-line source and writing the downloaded testing program into a second section of the RAM by the duplicated booting program; and enabling the downloaded testing program to check a third section the rest part of the RAM excepting the first and second sections, after the downloaded testing program is executed by the duplicated booting program.