The dynamic capacity increasing technique exploits the potential power transmission capacity of overhead conductors by assessing ampacity in real?time. However, the existing dynamic capacity increasing models face challenges such as the requirement for a large number of sensors or difficulties in the installation and maintenance of sensors. To address these issues, a dynamic environmental measurement decoupling model is proposed. Firstly, the model establishes the associated equations between transient temperature data of aluminum spheres and environmental variables. Subsequently the solution accuracy of each environmental variable from the perspective of sensitivity is analyzed, and the solution methods of environmental variables with different sensitivities are given. Finally, experiments are carried out to validate the accuracy of the environmental measurement decoupling model. The experimental results show that the calculation error of the model is less than 4% compared with the calculation results of IEEE Std 738?2012.