To ensure the safety of the water conveyance tunnels in the operation period, effective dynamic monitoring indexes should be established according to the engineering characteristics. Based on the analysis of the monitoring methods and the influence factors of operation security, a safety monitoring model of water conveyance tunnel is established. The proposed model considers the influence factors such as internal and external water pressure, temperature, deformation of lining concrete and surrounding rock. The monitoring indexes are determined by the confidence interval method. The long-period monitoring data are segmented and analyzed, and the moving average filtering algorithm is introduced to determine the dynamic monitoring indexes for water conveyance tunnels. The calculation result of an engineering example shows that the dynamic monitoring indexes at measuring points can be determined by the proposed method.