An electronic device with a solid state drive and associated control method are provided. The electronic device includes: a host; a power supply component, for providing electric power to the host and the solid state drive; and the solid state drive including a control unit electrically connected to the host through a bus, a cache memory electrically connected to the control component, and a flash memory electrically connected to the control component. When a remaining power of the power supply component decreases to a threshold value, the host controls the solid state drive to enter a data secure mode and disables the cache memory; and when the remaining power of the power supply component is above the threshold value, the host controls the solid state drive to enter a high performance mode and enables the cache memory.