Objective To make biomechanical evaluation on ultimate pullout strength of the suture anchors based on the angle of suture anchor (SA) implanted into the humerus during arthroscopic rotator cuff repair (RCR) surgery. Methods Polyurethane materials with densities of 0.16 g/cm3 and 0.32 g/cm3 were used to simulate osteoporosis and normal cancellous bone, and polyurethane materials with densities of 0.64 g/cm3 and 3 mm thickness were used to simulate human cortical bone. The two kinds of cancellous bone models were respectively adhered together with cortical bone model to construct human humerus model. Titanium metal suture anchors were inserted into humerus models at 45°, 60°, 75° and 90° angle, then the continuous tensile experiments were performed, and 45° pulling direction between the humerus model surface and suture anchor was used to simulate the supraspinatus physiological traction direction, and each group was continuously tested 8 times, recording the pullout strength and failure modes. ResultsThe pullout force of high-density bone models was significantly higher than that of low-density bone models (P＜0.001), and at the same density, compared with 45°, 60° and 75°, the implant angle of 90° has a larger pullout force (P＜0.01). Conclusions In the model of humerus, the 90° implantation of suture anchor showed better biomechanical properties, and the vertical implantation of anchor in the repair of rotator cuff was beneficial to the knotting during operation and postoperative recovery of the supraspinatus.