The electronic knee joint gap balance measurement device that employs multi-fusion sensing technology is an intelligent electronic measuring device for knee joint gaps, which allows for intuitive reading, high accuracy, ease of measurement, and easy promotion. It can assist orthopedic surgeons in achieving satisfactory gap balance during knee replacement surgeries, thereby improving surgical outcomes. This study develops a low-cost, high-precision, and user-friendly knee joint gap measuring instrument based on TRIZ theory. Through problem analysis, TRIZ solutions, and ergonomic design, a measurement device integrating various sensors has been created. Testing of the prototype and validation through actual operations by surgeons show that this device measures the joint gap formed after osteotomy using electronic calculations. It can obtain precise data within the gap effectively avoiding errors caused by subjective measurement methods and significantly enhancing the work efficiency of orthopedic surgeons as well as the precision of surgeries, demonstrating good application and promotional value.