In order to study the influence of ice sheet on the local scour of composite piers and the distribution of flow field around them, the influence of different flow conditions and pier sizes on the local scour of composite piers was analyzed under different cover conditions based on the scour test of moving bed. The empirical equation for predicting the maximum thrust depth of composite pier under the conditions of open channel flow and overburden flow was established, and the flow field in front of the piers was measured by ADV. The results show that the scour pattern of composite pier is similar to that of tandem pier, and the maximum scour depth always appears in front of the pier. The depth of incoming flow, incoming flow velocity, pier size and ice sheet roughness are positively correlated with the maximum scour depth. In the rough ice-overburden flow condition, the maximum vertical velocity in front of the pier is the highest, resulting in greater maximum scour depth than that of open channel flow and smooth ice flow under the same condition.