An on-line optoelectronic differential measurement system used for glass thickness measurement in the float glass molding zone of the tin bath under the high-temperature environment is introduced.A model of single camera and two dimensional binocular vision sensors

which can compensate the lean of the both surfaces of the glass automatically

is introduced.And this model alters the dual camera structure into the single camera structure.By a couple of symmetrical mirrors

the single camera is imaged as two virtual cameras

and the two parallax images of the same object can be collected in the same active area of charge coupled device（CCD）.Therefore

it eliminates the system error brought by the lean of the glass board

at the same time it accomplishes the two dimension orientation and then guarantees the accord between the instrument benchmark and the measurement benchmark.After analyzing the influence on the performance of the laser measuring system brought by the fluctuation of the laser transmission line and the ray under the condition of high-temperature turbulent flow

a transcendental compensation method used to compensate the high-temperature optical system error is presented.It is proved by the experiment and the on-line practical application that the measuring system meets the requirement of the on-line glass thickness measurement.