In order to improve the efficiency of the low-speed wind tunnel strain-gauge balance, a method for judging the polarity of the balance channel by direct single-component loading is proposed. By estimating the results of single component loading, the balance calculation results of different channel polarity combinations are screened. The experimental results show that the method can quickly and effectively judge the polarity of the balance channel, and does not rely on experience, supports automatic programmed operation, and has low requirements for loading accuracy, and is easy to meet the practical requirements.