The health monitoring study for long-span bridges has become a hot topic in civil engineering.However,because of its complexity and particularity in bridge structure,monitoring variables are greatly influecnced by environmental factors,which results in more difficulties in evaluation.The paper analyzes structural responses in different temperature fields,and the research results show that effect of temperature difference among members and temperature gradient on bridge stuctuie is remarkable.The resultis may be of reference for bridge health monitoring strategies.