The invention discloses an automatic detection machine for an SMT printing steel mesh. The detection machine comprises a Y-direction translation mechanism, a steel mesh supporting and pressing mechanism, an X-direction translation mechanism, and a detection mechanism. The X-direction translation mechanism and the Y-direction translation mechanism are in an X axis direction and a Y axis direction, wherein the two directions are perpendicular to each other on a horizontal plane. The Y-direction translation mechanism consists of a shock-absorbing seat, a pedestal, a Y-direction guide rail and a sliding block, a Y-direction sliding table, a bar-shaped light source, a Y-direction grating ruler and a Y-direction lead screw and a nut. The steel mesh supporting and pressing mechanism includes a movable support, a fixed support, a steel mesh support plate, a Y-direction limiting block, a compression cylinder, a steel mesh adjustment guide rail and a slide block thereof. And the X-direction translation mechanism is composed of two X-direction guide rail mounting seats, two X-direction guide rails and a slide block thereof, an X-direction lead screw and a nut, and an X-direction grating ruler. The detection mechanism includes a camera connection plate, a camera, a tensiometer connecting plate, a tensiometer, and a tensiometer lifting regulation element. The detection machine has advantages of high detection precision and wide application range.