A device and method for controlling traffic transmission/reception in a network end terminal is provided. The method includes measuring a transmission/reception processing performance value of a first network stack and a transmission/reception processing performance value of a second network stack according to each central processing unit (CPU) core, reserving network performance required for an application on the basis of the transmission/reception processing performance value of the first network stack and the transmission/reception processing performance value of the second network stack measured according to each CPU core, and allocating a CPU core corresponding to the reserved network performance to a networking thread of the application to control traffic transmission/reception.