Hybrid-Electric Vehicle (HEV) which combined the electric motor with auxiliary power unit in a car driven is introduced. Characteristic of Hybrid-Electric Vehicle are different from the other vehicle, in the structure of Hybrid-Electric Vehicle, Integrated Starter Generator (ISG) electrical system can achieve high efficient performance of driving and generating electricity simultaneously. These systems adopt the sum torque through engine and generator, the motor connected transmission through engine. According to the requirements of different conditions, the torque of motor and transmission are compound in various forms to achieve optimal driving efficiency.This study developed a dynamometer to measure the relationship between locked torques with temperature rises of an Integrated Starter Generator motor used in electrical vehicles. The dynamometer adopted an AC motor to obtain the relationship between drive and load functions, which developed in this study can perform real-time measurements and storage of measured data obtained from the dynamometer. Experiments for measuring temperature rise of ISG motor were performed at three different conditions, namely 56 Nm locked rotor torques and 18.8A locked rotor current; 57.1Nm constant torque at 1050rpm; constant power with 14.3Nm and 4050rpm, respectively. Based on the theory of temperature rise, the temperature rises of motor are 14K, 33.1K, and 16.01K for the tested cases respectively. Measured results show that the performance of motor system is satisfied with the design.