The invention provides a testing device and a testing method for a reciprocal reflective optical voltage sensing unit. The device comprises a light source, a polarizer, a polarization-maintaining circulator, an optical voltage sensing unit, an analyzer and an optical power tester, and a first port, a second port and a third port are arranged on the polarization-maintaining circulator. The method includes: setting a first testing point, a second testing point and a third testing point in the testing device; respectively performing 0-degree welding to the first testing point and the third testing point; respectively measuring optical power output by the testing device when the second testing point is subjected to 0-degree welding and 90-degree welding through the optical power tester, and testing whether performances of the optical voltage sensing unit are good or not through judging whether optical signals exist or not. By the testing device and the testing method, the performances of the optical voltage sensing unit can be effectively tested through judging whether output signals exist or not. The testing device has the advantages of simple structure, convenience in operation, accuracy in testing result and the like.