The invention provides a central processing unit control method and device. The CPU (Central Processing Unit) of a terminal comprises a plurality of CPU cores. The method comprises the following steps: monitoring the loading condition of the CPU; and according to the loading condition, controlling the first CPU core in the CPU to be in a startup state or a shutdown state, wherein the first CPU core is the CPU core of which the operation frequency is higher than the operation frequency of other CPU cores in the CPU. By use of the center processing unit control method, power consumption generated by starting a big core can be lowered, and terminal heating possibility can be lowered.