Abstract: A linear ball guide assembly for guiding a load to move smoothly and linearly along the guide rail at low frictional resistances, including a straight guide rail, a slide block, a pair of end caps, a pair of cover plates for U-shaped ball turning grooves, a pair of loaded ball retainers and two loops of balls. Both sides of the guide rail and inner sides of the slide block are formed with linear Gothic ball grooves for increasing the load capacity of the ball guide assembly. Above the ball grooves, two recirculating holes are formed on the slide block for the recirculation of balls. The end cap is formed with U-shaped ball turning grooves for guiding the loaded balls into the recirculating holes of the slide block. The balls then go through the U-shaped ball turning grooves of the opposite end cap back to the Gothic ball grooves to complete the recirculating loop of the balls between the slide block and the guide rail.