The invention belongs to the technical field of printing and packaging machinery, and specifically discloses a bottom varnishing system. The bottom varnishing system comprises a platform base, whereina transversal adjustment plate is connected to the top of the platform base in a clamping manner; and a longitudinal adjustment plate is connected to the top of the transversal adjustment plate in aclamping manner. According to the bottom varnishing system, the square platform base is welded to the bottom of a rack, the transversal adjustment plate and the longitudinal adjustment plate are fixedto a platform, and four guide columns are installed at the top of the longitudinal adjustment plate, and used for being cooperated with a hydraulic cylinder to adjust the overall lifting position ofa varnish basin and a varnishing varnish wheel; and a motor drives a wheel shaft of the varnishing varnish wheel to rotate, a gear is installed at the other end of the varnishing varnish wheel, the gear drives a small rubber coating wheel and a large rubber coating wheel to rotate, and the large rubber coating wheel carries the varnishing varnish and transfers the varnishing varnish onto a productto realize varnishing. The varnishing weight of the bottom is at the lower part, the square platform is solid and stable, and easy and time-saving in adjustment, the shortage of downward dripping leakage of the varnish is solved, and the problem of stripes in the varnishing effect, which is caused by swinging, is solved.