A method of taking a picture when the memory of a digital camera is already full, includes: judging whether the memory of the digital camera is full; if yes, allowing the digital camera to continue to take a picture; next, storing the picture in an SDRAM or a DDR SDRAM of the digital camera; next, determining whether to retain the picture by using a preview function of the digital camera; if yes, selectively deleting a part of data that is stored in the memory, via a browsing function of the digital camera, for sparing the memory a predetermined space; and, storing the picture in the predetermined space. Hence, the method solves the problem that when the memory is full and the user wants to take another picture, old pictures must firstly be deleted. Hence, the user often loses the chance to take a picture that he/she wants.