Long cylindrical guide rods are widely used in large industries such as turbine power systems, defense equipments to guide bowls. These cylindrical guide rods (having lengths in meters) require precision form control like straightness. This straightness parameter can’t be measured using conventional techniques where longer datum is unavailable or using angle measuring devices directly. This paper aims to evolve a new measurement method for checking the straightness of a long cylindrical guide rods by an autocollimator with the aid of the Precision level. This newly developed method is validated by comparing the straightness results of precision cylinder (length of 500 mm) using the conventional method.