The invention provides a method and a system for enhancing a text image based on a stroke operator. The stroke operator is introduced into image enhancement processing, strokes and background can be intelligently distinguished through the stroke operator, the stroke is deepened, and the background is denoised, so that the aim of enhancing a reading effect can be effectively fulfilled; moreover, the stroke operator, binarization and expansion operation are adopted, so the calculation amount is small, the performance is good, and the real-time requirement can be met; moreover, the technology is easy to implement, technical barriers are avoided, the method and the system are low in cost and risk and have a wide application range, can be used for image enhancement in a handheld reader, and can also be used for the image preprocessing step for optical character recognition.