Abstract: Recently, grating-based phase contrast X-ray imaging has become a hot spot, and it is considered the key technology for future clinical medical nondestructive diagnosis due its high compatibility with the conventional X-ray source. Compared with the existing X-ray absorption contrast imaging technology, phase-contrast imaging has the unique ability to distinguish soft tissues. Here the grating-based phase contrast X-ray imaging was used to nondestructively detect the structure of local crucian carp treated by formalin. The structure of the intestine tissues are shown clearly, the very first time using such imaging technology.