The invention discloses a real-time detection system for wood microstructure characteristic changes, which comprises a loading unit, a microscopic unit, an image acquisition unit and an image processing unit, wherein the loading unit is used to stretch, compress, bend, twist or cut to-be-detected wood; the microscopic unit is used to magnify a to-be-detected area of the wood; the image acquisition unit is used to acquire surface image information of the area magnified through the microscopic unit; and the image processing unit is used to receive image information acquired by the image acquisition unit, calculate and obtain the micro-area strain information and the real-time microstructure change results of the to-be-detected wood. The system can measure micro-area tissue and cell strain to realize micro-area deformation quantization, and can monitor micro-area defects.