A system for producing needle coke, comprising: a coke tower provided with a feedstock inlet and an oil gas outlet, where a hydrocarbon-containing feedstock is reacted to produce needle coke and oil gas; a pressure stabilization tower provided with an oil gas inlet, an overhead light fraction outlet, a bottom oil outlet and a cycle oil inlet, where the oil gas from the coke tower is received and separated into an overhead light fraction and a bottom oil, and a pressure controller is provided at the top of the pressure stabilization tower for adjusting the pressure at the top thereof; a buffer tank provided with an inlet, a first bottom oil outlet, and a second bottom oil outlet, for receiving the bottom oil from the pressure stabilization tower and providing a buffering action; and a coking fractionation tower provided with an inlet, a light oil outlet and a heavy oil outlet, where the bottom oil from the buffer tank is received and separated into a light oil and a heavy oil; wherein the oil gas outlet of the coke tower is in communication with the oil gas inlet of the pressure stabilization tower through a pipeline, and no pressure controller for adjusting the pressure at the top of the coke tower is provided in the coke tower or on the oil gas pipeline connecting the coke tower to the pressure stabilization tower, the inlet of the buffer tank is in communication with the bottom oil outlet of the pressure stabilization tower, the first bottom oil outlet of the buffer tank is in communication with the cycle oil inlet of the pressure stabilization tower through a pipeline with a temperature adjuster provided thereon, and the second bottom oil outlet of the buffer tank is in communication with the inlet of the coking fractionation tower, and optionally, the heavy oil outlet of the coking fractionation tower is in communication with the feedstock inlet of the coke tower. a coke tower provided with a feedstock inlet and an oil gas outlet, where a hydrocarbon-containing feedstock is reacted to produce needle coke and oil gas; a pressure stabilization tower provided with an oil gas inlet, an overhead light fraction outlet, a bottom oil outlet and a cycle oil inlet, where the oil gas from the coke tower is received and separated into an overhead light fraction and a bottom oil, and a pressure controller is provided at the top of the pressure stabilization tower for adjusting the pressure at the top thereof; a buffer tank provided with an inlet, a first bottom oil outlet, and a second bottom oil outlet, for receiving the bottom oil from the pressure stabilization tower and providing a buffering action; and a coking fractionation tower provided with an inlet, a light oil outlet and a heavy oil outlet, where the bottom oil from the buffer tank is received and separated into a light oil and a heavy oil; wherein the oil gas outlet of the coke tower is in communication with the oil gas inlet of the pressure stabilization tower through a pipeline, and no pressure controller for adjusting the pressure at the top of the coke tower is provided in the coke tower or on the oil gas pipeline connecting the coke tower to the pressure stabilization tower, the inlet of the buffer tank is in communication with the bottom oil outlet of the pressure stabilization tower, the first bottom oil outlet of the buffer tank is in communication with the cycle oil inlet of the pressure stabilization tower through a pipeline with a temperature adjuster provided thereon, and the second bottom oil outlet of the buffer tank is in communication with the inlet of the coking fractionation tower, and optionally, the heavy oil outlet of the coking fractionation tower is in communication with the feedstock inlet of the coke tower.