The strength and rigidity of the bridge superstructure are deduced from the measurement of the stress and deflection of the bridge under the most disadvantageous load through loading test on Xiaowan Bridge.According to the improtance of bridge loading test,the conditions for bridge loading test are summarized,the objective,contents and peocess of static test of a bridge are in detail introduced,the theory should be sufficiently combined with practices when the loading test of the bridge is conducted so that accurate evaluation on the bridge can be made.