The invention discloses an improved ball rack structure of reduced size.The improved ball rack structure comprises four supporting column bodies and eight connecting columns, wherein every two equal-length connecting columns form a group and are staggered and connected in a pivoted mode to form a connecting column group, and the equal-length connecting column groups are oppositely arranged and are connected to ejecting sleeve portions fixed on the four supporting column bodies or sliding sleeves slidably arranged on the four supporting column bodies in a pivoted mode.The bottom end of each connecting column is arranged on the corresponding independent sliding sleeve in a pivoted mode, so that the eight connecting columns are provided with the eight matched sliding sleeves for pivoted connection of the columns.Therefore, even if the eight connecting columns are different in length, an unfolded ball rack can be square or rectangular, the number of accommodated balls can be larger, and the best closing-up effect of complete closing up can be reached during closing up of the ball rack.