Abstract: Since it is difficult to obtain stratigraphic cores in deep exploration wells, a hydraulic rotary sidewall coring tool with a maximum operating temperature of 205 °C and high reliability was developed. The coring tool is composed of a ground system, a control acquisition short section, and a mechanical hydraulic section, and adopts an integrated thermos bottle technology, passive thermal management technology, and stuck-freeing technology, which effectively improve its temperature resistance and engineering safety. The performance of these key technical functions was verified through simulation and ground tests. The actual operation results show that the tool can operate normally in exploratory wells with a high temperature of 189 °C and high pressure, high relative density of drilling fluid, and large formation pressure difference, and further, the average core recovery rate exceeds 90%. In addition, it has the characteristics of high temperature resistance, stick and jam prevention, and high coring efficiency and core recovery rate and shows excellent adaptability and high safety and reliability in solving problems in complex well sections, such as hole enlargement, hole contraction, and borehole collapse.