The invention relates to a device and method for testing scanning speed and uniformity of a pendulum mirror. The device is composed of a hollow cylinder holder, a CMOS (complementary metal oxide semiconductor) camera, a line laser group and a control system, digital image signals of reflected light rays of the pendulum mirror are acquired with the CMOS camera and an image acquiring card by the aidof features that a to-be-measured object-pendulum mirror can reflex laser and by arranging the ring-type line laser group, and high-precision angular velocity of the pendulum mirror is acquired according to the digital image signals. The measurement precision in scanning uniformity can reach 3X10<-5>, and the existing testing method is greatly improved in precision.