The invention discloses a double-curvature circular-arc curved-surface roller way structure for a heavy-load ball screw. The small roller way curvature radius is adopted when the contact angle formedbetween a roller way and a ball ranges from 0 degree to 40 degrees and ranges from 50 degrees to 90 degrees, the large curvature radius is adopted when the contact angle formed between the roller wayand the ball ranges from 40 degrees to 50 degrees, and equations of normal plane cross sections are established in a sectional mode. The contact angle formed between the roller way and the ball is basically about 45 degrees when the ball screw bears small loads, the contact angle can be increased when the load borne by the ball screw is increased, the bearing capacity of the ball screw is improvedwhen the contact angle is increased to 50 degrees or above as the curvature radius of the roller way is decreased, and then the bearing capacity is improved.