The disclosure discloses a neural-network computing system. The system includes: an I / O interface, which is used for I / O of data; a memory, which is used for temporarily storing a multi-layer artificial-neural-network model and neuron data; an artificial-neural-network chip, which is used for executing multi-layer artificial-neural-network operation and a back-propagation training algorithm thereof, wherein data and a program from a central processing unit (CPU) are accepted, and the above-mentioned multi-layer artificial-neural-network operation and the back-propagation training algorithm thereof are executed; the central processing unit CPU, which is used for data transportation and starting / stopping control of the artificial-neural-network chip, is used as an interface of the artificial-neural-network chip and external control, and receives results after execution of the artificial-neural-network chip. The disclosure also discloses a method of applying the above-mentioned system forartificial-neural-network compression encoding. According to the system, a model size of an artificial neural network can be effectively reduced, data processing speed of the artificial neural network can be increased, power consumption can be effectively reduced, and a resource utilization rate can be increased.