Small defects existing in the production and installation of 10 kV cable accessories are easy to cause failures, so it is of great significance to study effective insulation performance evaluation methods. A comprehensive insulation performance evaluation method considering small defect disturbance is proposed. The precision analysis method of electric field strength is proposed, its accuracy is verified by comparison with the analytical solution. It is confirmed that the electric field strength distortion is the most serious when the small defect is located at the insulation interface in the accessory. Based on the cable accessories from nine different manufacturers, models with small defects on the insulation interface in the accessories are made; Based on the pulse current method, the key parameters of partial discharge of different models with and without defects are measured under the same measurement accuracy; The comprehensive insulation performance is determined by the analytic hierarchy process. The results show that small defects have great influence on the comprehensive insulation performance of cable accessories, which verifies the necessity of considering the ability of accessories to resist small defect disturbance.