To study the influence of the enlarging hole position and the long side size of the slotted hole on the slip resistance of friction-type high strength bolt connections, the slip resistance bearing capacity test was carried out on six specimens, in which the bolt hole types were standard round holes and slotted holes, respectively. Firstly, experimental studies were conducted to investigate the load-slip relationship, anti-slip bearing capacity, load reduction factor, friction surface anti-slip coefficient, and wear patterns of the hole contact surface in connection components. Then, based on the experimental data, a finite element model was developed and validated. Finally, finite element analysis was performed to reveal the mechanism of how hole expansion affects the anti-slip performance of the connection components. The results show that, compared with standard bolt round-hole specimens, the anti-slip bearing capacity of slot-hole specimens decreases by 12% to 29%. Moreover, the impact of cover plate hole expansion on the anti-slip bearing capacity of bolt connections is more significant than that of core plate hole expansion. The finite element model simulated the load-slip curve, and the test curve is basically in line with the model. Therefore, the model can be used to analyze the anti-sliding performance of friction high strength bolt reaming connectors.