The present invention relates to a frame panel having an improved reinforcing pattern. The frame panel includes a panel body having a front plate and a rear plate, which are integrally formed as a single body through a blowing process. The front plate has vertical groove patterns and horizontal groove patterns on the outside area except for the central area thereof, while the rear plate has vertical groove patterns and horizontal groove patterns on each of the central area and the outside area thereof, thus forming rectangular reinforcing groove patterns, with a diagonal groove pattern diagonally extending upwards from the lower end of a side of the rectangular reinforcing groove pattern provided on the outside area of the rear plate such that the diagonal groove pattern passes through the rectangular reinforcing groove pattern provided on the central area of the rear plate. Due to the location, orientation and depth of both the hollow pattern and the groove patterns, the present invention realizes lightness of the frame panel, provides excellent structural strength of the frame, panel, and remarkably reduces the manufacturing cost of the frame panel.