Uncertainty of Wheatstone bridge-arm and uncertainty of electric bridge's sensitivity are analyzed in detail, accordingly combined uncertainty of Wheatstone bridge and examples for these are given. 本文分析了惠斯通电桥桥臂引入的不确定度和电桥灵敏度引入的不确定度,从而给出惠斯通电桥的合成不确定度,并举例说明。