The invention relates to a large-format high-speed high-precision automatic optical detector, belongs to the field of automatic optical detection, and solves the problem that the detection precision tends to be influenced by different errors when a mobile small-view-field lens is moved in a present automatic optical detector. The detector comprises a support platform, damping supports, a translation guide rail pair, a workbench on the translation guide rail pair, a transmission illumination light source, a precise driver, a control system, a grating ruler, a lens support, a reflection illumination light source, a reflector, a precise focusing platform, a large-view-field high-precision lens and a splicing detector focal plane assembly. The imaging view field of the large-view-field high-precision lens is greater than 750mm, an imaging focal plane is composed of a triangularly spliced detector array, and part or all spliced detectors are controlled to work in different frame frequencies to match the movement speeds of different workpieces. The large-view-field high-precision lens is combined with the multi-detector spliced focal plane, the problem that a single lens cannot realize large-view-field imaging but multiple lenses are inconsistent in imaging is overcome, and the detection precision and efficiency are improved.