In order to eliminate the effect to the optical current transformer by the liner birefringence which changes with the temperature,the idea of optical balanced bridge current transformer is advanced,and the principle is also given;analytical expression of azimuth angle variation is deduced that is produced by liner birefringence,the direction of 1/2 wave plate axis is also calculated which is used to eliminate the effect of the liner birefringence. The working principle and signal processing method of the optical balanced bridge are given,the expression that used to calculate the current is deduced. It is proved that the current transformer output error is within 2.96% when the temperature changes between 20 ℃ and 65 ℃ as the current is 2 A. The advancement of optical balanced bridge current transformer solved the problem of the effect to the system produced by the birefringence along with the variation of temperature which could not be solved using the traditional methods. This new method will boost the utility of optical current transformer.