The present invention discloses a RFID testing system, comprising an object-under-test having a RFID tag attached thereto, a RFID reader and a tester. Wherein, the tester further comprises: a base; a bar-shaped first rail, mounted on the base in a stationary manner; a bar-shaped second rail, perpendicularly and slidably mounted on the first rail for enabling the second rail to move linearly along the first rail; a bar-shaped third rail, slidably mounted on the second rail and disposed perpendicular to the first and the second rails for enabling the third rail to move linearly along the second rail; and a clamping device, slidably mounted on the third rail for enabling the clamping device to move linearly along the third rail.