The double-roller-guide involute measuring instrument is a kind of involute measuring instrument with no Abbey error, few error sources, and high measurement accuracy, which is commonly used to measure the class-1 gear involute artefacts or class-1 standard gears. However, it is not easy to obtain the accurate correspondence between the profile deviation and roll path length of the measured involute with the double roller-guide involute measuring instrument. The root of the involute flank is prone to accumulate machining and measurement errors, while the profile deviation of class-1 gear involute artefacts is required the to be calculated from 3 or 5 mm of the roll path length, which may lead to large profile measurement deviations if the roll path length is off. To obtain a more accurate correspondence between profile deviation and roll path length, and to achieve a more accurate evaluation of gear involute artefacts, the effect on the roll path length caused by the tip corner chamfer, deviation of tip radius and deviation of roller radius as measuring gear involute artefact with double roller-guide involute measuring instrument is analyzed. Tip corner chamfer and deviation of roller radius could lead to deviations in roll path length of millimetres. In addition, a kind of measuring strategy for a double roller-guide involute measuring instrument based on machine vision is proposed. The theoretical tip point and the starting measuring position of the gear involute artefact are obtained by machine vision and the roll path length is corrected according to the roller radius. A measurement experiment is also implemented on a gear involute artefact, the difference in the profile form deviation between the double roller-guide involute measuring instrument and the gear measurement centre is no more than 0. 1 μm, and the profile deviation curve is consistent. It shows that the measurement strategy could obtain the correspondence between profile deviation and roll path length.