[Purposes] This paper aims to investigate the influence of the powder binder ratio, temperature, and stress level on the creep properties of asphalt mortar. [Methods] Creep tests were conducted on asphalt mortar beam specimens with different powder binder ratios using bending beam rheometer (BBR) at different stresses and temperatures. The creep compliance model of asphalt mortar coupling powder binder ratio, temperature, and stress level was built according to the test results. [Findings] The creep compliance of asphalt mortar decreases with decreasing temperature, and the reduction varies significantly among asphalt mortars with different powder binder ratios. Under the same temperature and stress conditions, the creep compliance decreases as the powder binder ratio increases. The creep compliance of asphalt mortar with different powder binder ratios increases with increasing stress level. Especially in the case of low powder binder ratios, the creep compliance of asphalt mortar increases greatly with the increase in stress level. [Conclusions] The proposed creep compliance model can provide theoretical and experimental support for the proportion design of asphalt mortar and the optimization of its creep resistance.