Abstract:An introduction about the structure and types of G protein and a review of its function in Visual Transmission, regulating Hypertension, Arrhythmia and Hemorrhagic shock and controlling the occurance of tumor is given in detail in the paper. The results show that G protein has a wide presence in the sensitive organs of animals and plays an important role in the process of visual transmission; the content of mRNA in G protein changes when Arrhythmia occures and when Hemorrhagic shock takes place; the content of G protein in the heart and lung also has significant change; mutations of certain G protein subunit gene can cause the deletion or expression changes of subunits, which may cause some physiological dysfunction, or even a cancer. So G protein participates in the course of Animal Visual Transmission, regulating Arrhythmia and Hemorrhagic shock and controlling the occurance of tumor. It remains in doubt whether the G protein is related to hypertension. The focus of the future development will fall on the establishment of G protein subunit gene structure, G protein gene cloning and its control of gene expression and new pharmaceutical medicine design and synthesis.