It's difficult to accurately calculate the value of the conductor temperature using the currently available methods since it is not only influenced by the line load， but also related to tension and environmental factors such as wind speed， wind directions， and sunshine. Based on an investigation on the relationship between them and by transforming a nonlinear issue into a linear one， a mathematical model for the conductor temperature is developed using the multiple logistic regression analysis. Field results show that this conductor temperature model is effective in describing the relationship between the line state parameters and environment and calculating the average conductor temperature.