The invention relates to an environment factor monitoring and finite element-based underground power cable current-carrying capacity online prediction system and an environment factor monitoring and finite element-based underground power cable current-carrying capacity online prediction method. The system consists of a temperature sensor used for measuring the air temperature, a wind speed sensor, a humidity sensor, a singlechip system and a scheduling host of a power department. The method comprises the step of predicting the current-carrying capacity of an underground power cable by combining temperature, wind speed, humidity and other data measured in real time with the calculation of a finite element temperature field. The system and the method have the advantages that: the system andthe method can accurately predict the current-carrying capacity of the underground power cable on line, so that the power department can develop the capacity of conveying electric energy to the greatest degree; meanwhile, the system and the method can avoid the resource waste phenomenon of wasting the talent on a petty job on the premise of guaranteeing safe and reliable operation.