A ballistic trajectory method for a golf ball is disclosed wherein a ballistic trajectory of a golf ball having a plurality of dimples formed on the surface thereof when the golf ball is hit to fly at an arbitrary number of rotations and an arbitrary initial speed can be estimated and ballistic trajectory and flight characteristics of the golf ball can be evaluated without depending upon experimental evaluation which is based on an actual model thereby to allow a golf ball to be developed efficiently. The ballistic trajectory of the golf ball when the golf ball is hit to fly is estimated by successively calculating the flight distance and the height of the ball after every lapse of a very short period of time after the ball is hit to fly until it drops to the ground making use of arithmetic operation by a computer.