The invention discloses an automatic transformer station digital relay protection tester. The tester comprises a central processing unit, and a time setting unit, a light output/input unit and a small signal output unit which are respectively connected with the central processing unit, wherein the central processing unit is used for communication with an industrial control computer, input and output of a light digital portion, synchronization and communication with a CPU, time setting and small signal output. The tester provided by the invention can automatically read fixed values of a protection apparatus, a measurement and control apparatus and an intelligent terminal and can inspect the communication consistency between the protection apparatus, the measurement and control apparatus and the intelligent terminal.