Abstract: The measurement accuracy of multiple-arm caliper is affected by many factors.According to measuring principle of multiple-arm caliper,in combination with the actual operation situation,from the angles of instrument mechanical structure,external working environment,the operation conditions and data interpretation,the factors that affect measuring precision have been analyzed,and it has been verified by the ground experiments.In the end,the influencing degree of these factors has also been analyzed,and the methods and measures to reduce or eliminate the adverse effects have been provided.The field application effect is good and it improves the measurement accuracy.The research results can provide better guidance for the arm caliper measuring technology of field application.