The invention relates to mechanical error detection, and solve problems in the prior art that a device is not portable and difficult to operate. The device realizes to measure perpendicularity error of a coordinate measuring machine, and further error compensation provides original error data, and promotes measuring precision improvement of the three-coordinate measuring machine. A technical scheme is that a device and a method for perpendicularity error detection of a three-coordinate measuring machine of an L-type ball array are provided, and the device comprises a base, a connecting rod, and a ceramic ball. The ceramic ball is bonded to the connecting rod. The connecting rod is fixedly matched with the base through bottom threads. The upper end of the threads is provided with a tool withdrawal groove. The middle part of the connecting rod is provided with a mounting hole, and the top end is bonded with the ceramic ball. The base is L-shaped, and is provided with 5 to 10 threaded holes at equal interval on the middle along the two L-shaped vertical arms. The device and the method are mainly applied to mechanical measurement applications.