The invention relates to a testing system and a testing method for safety and sensitivity of a relay protection setting value. The testing system comprises the components of an interference recording device which receives a protection setting value, an SV message and a GOOSE message and generating a COMTRADE file and an interference event short report, and transmitting the protection setting value, the COMTRADE file and the interference event to a background system; and the background system which determines the protection scope of a to-be-evaluated safety margin, calculating protecting action coverage based on the interference data and acquiring safety and sensitivity of the protection setting value on the interference condition according to the received protection setting value, the COMTRADE file and the interference event. According to the testing system and the testing method, through acquiring the actual interference data of a power grid, safety and sensitivity of the protection setting value which is related with the interference data are evaluated, and online estimation on an offline short-circuit current calculation result is realized.