The distributions of heat flux along the height and the circumferential direction of round billet mould were measured continuously. The influence of casting speed, carbon content, powder, and pouring temperature on the average longitudinal and circumferential heat flux in the "high heat flux region" was discussed. The experimental and analytical results provide a basis for an intelligent mould with online detection of defects, adjustment of operational parameters, optimization of the monitoring system, and even prediction of abnormal heat transfer.