Precise bone resection is mandatory for kinematically aligned total knee arthroplasty（KA-TKA). Patient-specific instrumentation (PSI) has been applied to improve the accuracy of bone resection in TKA for many years. The purpose of this study was to investigate whether surgeons’ domination in PSI design can improve accuracy in KA-TKA. A total of 24 patients (24 knees) who underwent KA-TKA in our institution were assigned into engineer designed PSI group (10 knees) and surgeon designed PSI group (14 knees). The bone resection discrepancies of every key facets were used to evaluate the accuracy of PSI in bone resection, while the absolute differences of joint line orientation before and after surgery were used to evaluate the accuracy of PSI in joint line restoration. The overall discrepancy of bone resection was reduced by surgeon designed PSI compared to engineer designed PSI by 0.33mm (P<0.001). Surgeon designed PSI could reduce the outliers in terms of relative discrepancies in bone resection as well. Moreover, surgeon designed PSI could significantly improve the accuracy of PSI in the restoration of the joint line (p=0.01). This study indicate that the dominance of surgeons in both PSI design and subsequent surgical operation should be emphasized in efforts to improve the accuracy of PSI.