Abstract: To address the risks of electronic failure in existing high-temperature hydraulic rotary wellbore coring instruments during ultra-high-temperature operations, accelerated aging of internal components due to prolonged heat exposure post-operation, and the inability of a single electronic module to perform continuous coring within short intervals, an optimized design is proposed for the electronic module of ultra-high-temperature rotary wellbore coring instrument. The solution incorporates an integrated pressure-resistant thermal insulated bottle structure, enhanced thermal management system framework, and active cooling technology. Through synergistic heat insulation, storage, and conduction mechanisms, the design significantly enhances temperature regulation and operational availability. This effectively mitigates electronic device failures under extreme conditions (235 ℃/140 MPa), improves post-operation cooling efficiency, and enables consecutive operations. Field tests demonstrate high reliability in ultra-high-temperature well coring applications, providing technical guidance for analogous instrument development.