In order to investigated the main influencing factors of the error averaging ability of the orifice-compensated air bearing,an error motion prediction model of a single air pad was established,and the defined averaging coefficient was used to discuss the quantitative relationship among the error motion of the air pad,the form error of the rail and the structural parameters of the air pad.The results show that,for the long waves of the rail form error (with wave number from 0 to 1),when the wave number gradually increases,the averaging coefficient gradually decreases from 1 to close to 0.For the short waves of the rail form error (with wave number from 1 to 10),when the wave number is close to or equal to a positive integer,the average coefficient takes the minimum value close to 0.And when the wave number is close to or equal to a positive integer plus 0.5,the average coefficient takes the local maximum value less than 0.25.Among the structural parameters,the width of the air land has a great influence on the error averaging ability,while the air pad gap and the diameter of the orifice restrictor basically have no influence on the error averaging ability.When the moving speed is less than 10 000 mm/s,the moving speed has a very weak influence on the error averaging ability.