Abstract: We are developing a surgical support system for liver abdominal surgery to prevent surgical accidents. Our support system can detect proximity of certain body parts and can make a warning when the knife approaches the critical part to be excised, such as large blood vessels. The system has two distance cameras with different features, and these cameras are located above the operating table. One camera measures the liver shape and the other tracks the position of a surgical knife during surgery. In this report, to evaluate the accuracy of the distance between the position of the knife tip and the position of the blood vessels, the position and orientation of the liver were estimated using depth images of mock liver and virtual liver by simulated annealing algorithm, and the distance between the knife tip and the blood vessel in the mock liver was measured. The experimental results showed the maximum average error of the measured distance was 5.76 mm.