The invention discloses an automatic panel four-edge trimming saw comprising a guide rail base. a rectangular linear guide rail frame composed of four sets of linear guide rails are arranged on the guide rail base (1), a sliding table (2) is arranged on each set of a linear guide rail, a saw blade shaft (3) is arranged on each sliding table (2), a circular saw blade (5) is arranged on each saw blade shaft (3), a supporting plate platform (6) is arranged above the four saw blade shafts (3), and a pressing plate frame is arranged above the supporting plate platform (6). One end, where a circular saw blade (5) is installed, of each saw blade shaft (3) on each sliding table (2) faces toward the interior of the linear guide rail frame, when each circular saw blade (5) runs from one end of the linear guide rail where the circular saw blade (5) is positioned to the other end of the linear guide rail simultaneously, and the four edges of a panel can be cut off by the four rotating circular saw blades simultaneously. The automatic panel four-edge trimming saw is compact in structure, easy and convenient to operate, accurate and reliable in saw cutting, high in automaticity and high in production efficiency.