Dynamic monitoring device for external load deformation and crack extension of rock body

The utility model relates to a dynamic monitoring device for external load deformation and crack extension of a rock body. The dynamic monitoring device comprises a transparent sealed container, a rock body test-piece, a water filling and pressurizing device, a crack extension observation system and a deformation monitoring system, wherein the rock body test-piece is arranged in the transparent sealed container; an annular cavity between the rock body test-piece and the transparent sealed container is a confining pressure cavity; a stress sensor of the deformation monitoring system is mounted on the outer wall of the rock body test-piece; a confining pressure loading system is connected with the confining pressure cavity; the water filling and pressurizing device is connected to the middle of the rock body test-piece through a pipeline; the crack extension observation system is connected with the transparent sealed container. The dynamic monitoring device can be used for continuously and dynamically monitoring the crack extension generated by high-pressure water injection of the rock body to obtain a deformation state of the crack extension of the rock body for research on a crack extension situation of the rock body in a hydraulic fracturing process of the rock body.