This study investigates the temperature rise estimation of induction motor by back-propagation neural network (BPN) approach. The correlation analysis method is utilized to decide the input variables from the more influential factors on the temperature rise of induction motor. In practice, it is difficult to complete the temperature rise test because the test will spend 1-3 hours normally. A set of no-load data, such as no-load current, no-load power, no-load power factor, indoor temperature and temperature rise, are used instead to train the BPN. After training the BPN with the preceding data set, another set of no-load data, including no-load current, no-load power, no-load power factor and indoor temperature, are fed into the system to get the estimation of temperature rise. In this way, the measuring time of temperature rise can be reduced which may provide early discovery of the abnormal temperature phenomenon in the processes of manufacturing. Hence, a better quality of products and less manufacturing cost may be obtained.