Cable conductor temperature is a main factor affectingthe life and material utilization of the cable,and is an important parameter reflecting cable's operation state.However,it is difficult to directly measure the conductor temperature of in-use cables,so that a temperature calculation is necessary.In this paper,a model to calculate the transient temperature of cable conductor based on the support vector machine ( SVM) is proposed.In this model,both the load current and the skin temperature are used as the inputs and the conductor temperature is taken as the output.Moreover,in order to improve the calculation accuracy and avoid blind selection of training parameters,the particle swarm optimization ( PSO) algorithmis introduced in the model for optimizing the punishment index C and the core parameter γ.In addition,a comparison between the simulated and the experimental results is made,finding that the proposed PSO-SVM model is superior to the thermal circuit model and the BP neural network because it helps to obtain more accurate transient temperature and possesses good generalization ability.