The invention provides a high-pressure water conversion control device and a stress measuring system, and relates to the technical field of ground stress measurement. The high-pressure water conversion control device comprises a valve rod and a valve element rod; a valve cavity is formed in the valve body, and the inserting end of the valve core rod stretches into the valve cavity; the connectingend of the valve core rid is used for being connected with a drill rod; the valve cavity comprises a fracturing cavity, a setting cavity and a draining cavity which are sequentially formed in the axial direction; the fracturing cavity gets close to the inserting end of the valve element rod; the valve body is further provided with a fracturing pipeline communicating with the fracturing cavity, a setting pipeline communicating with the setting cavity, and a draining opening communicating with the draining cavity; a water outlet is formed in the position close to the inserting end of the valve element rod, and a water injection pipeline is arranged on the position from the water outlet to the connecting end in an extending mode; and the valve element rod can move in the valve cavity in the axial direction to enable the water outlet to communicate with the fracturing cavity, the setting cavity and the draining cavity. The technical problem that the weight of the existing drill rod appliesthe large pressure to a packer, and thus the potential safety hazard of pressing bursting of the packer exists is solved.