An improved pole frame structure of a foldable tent includes upright poles, side cross support rod assemblies, and a top support rod unit. The top support rod unit includes a top module provided with a limiting component, top support rod assemblies, and oblique support rods. One end of each oblique support rod is connected to the respective top support rod assembly by means of a slider provided with a stopper, and the other end of the oblique support rod is pivotally connected to the respective side cross support rod assembly. The structure enhances, by means of the stopper and the limiting component, the stability of the oblique support rods supporting tent cloth, and prevents the tent cloth from being damaged by the oblique support rods.