To maintain a high level of motivation is a vital issue during rehabilitation because rehabilitation involves much pain, depression, and discomfort. To study the mental state of patients is necessary. A new assistive approach using emotion evaluation combined with an assistive walking device to maintain motivation during the rehabilitation is proposed. To realize it, the walking-emotion relationship within personal walking limitation (PWL) was explored at first. The results showed that when people walked by following the personal preferred walking ratio (PPWR), they were evoked the arousal emotion and kept the current valence emotion simultaneously; however, when people were not following PPWR to walk, the negative emotion was elicited. After that, subject was required to wear the assistive walking device to conduct the test, which aims to observe the emotion variation when subject walked at specific walking gait with an assistive device. We then are according to current emotion state to tune device. The findings show if people mistakenly use the device, unpleasant feeling would be elicited. When we properly tuning assistive device conforms to current gait, it can validly alleviate the negative emotion further becoming the positive emotion. From these results, we conclude that emotion can be affected by walking. By using walking-emotion evaluation to an assistive device, we can be according to users' emotion to control device; also, we can use an assistive device to inspire users' emotion to further maintain motivation. Finally, this assistive approach provides a useful treatment way for serving rehabilitation.