The invention discloses 
measuring equipment and a measuring method for eccentricity ratios of a large-
diameter preform, belongs to the field of manufacture of 
optical fiber preforms, and relates to equipment and methods for measuring eccentricity ratios of preforms by 
mirror reflection measurement. The 
measuring equipment comprises a measuring table, a sliding table, a measuring table back plate, a detected 
data display screen, a data output display screen, a 
laser transmitting and receiving instrument support, an adjusting knob, a 
laser transmitting and receiving instrument, a rear linear guide rail, a left fixed roller bracket, a left support roller, a front linear guide rail, a graduated scale, a rotating motor, a moving bracket, a preform supporting rotating roller, a right fixed roller bracket, a right support roller, a left-right moving motor and a left-right moving lead screw. The measuring method includes steps of placing the preform on the left support roller and the right support roller on the left fixed roller bracket and the right fixed roller bracket, testing the surface of a body of the preform by the 
laser transmitting and receiving instrument in real time, recording data, collecting data of eccentricity ratios of various circumferential points around a first measuring point, computing an eccentricity ratio of the first measuring point by an eccentricity ratio computational formula; and measuring eccentricity ratio of a second measuring point.