The invention belongs to the technical field of precision measurement and the field of optical engineering and specifically relates to a portable array zeroing high precision laser large working distance auto-collimation device and method. The device consists of a light source, a collimating mirror, a reflecting mirror and a feedback imaging system; according to the method, via adjustment of the reflecting mirror, a reflected light beam is enabled to return to a center of an image plane of the feedback imaging system; an angular deflection measurement device on the reflecting mirror is used for obtaining angular variation of a surface of an object being tested. Because the reflecting mirror is added in a traditional auto-collimation angle measurement system, a problem that measurement cannot be realized when light reflected by the object being tested is deviated from a measurement system can be prevented; an auto-collimation working scope can be expanded while working distance remains the same or working distance is increased while the working scope remains the same; via specific design of the collimating mirror, the feedback imaging system, the reflecting mirror and the like, the portable array zeroing high precision laser large working distance auto-collimation device is enabled to be small in size, high in portability and great in measurement precision; stability of a measurement environment can be monitored, and a technical advantage of rapid measurement can be gained.