The present application discloses a processor and a method for executing an instruction on a processor. A specific implementation of the processor includes: a host interaction device, an instruction control device, an off-chip memory, an on-chip cache and an array processing device, wherein the host interaction device is configured to exchange data and instructions with a host connected with the processor, wherein the exchanged data has a granularity of a matrix; the off-chip memory is configured to store a matrix received from the host, on which a matrix operation is to be performed; and the instruction control device is configured to convert an external instruction received from the host to a series of memory access instructions and a series of computing instructions and execute the converted instructions. The implementation can improve the execution efficiency of a deep learning algorithm.