Gravity shear ratio and slab reinforcement ratio were adopted as the two test variables of competitive experiment to study the failure process of interior slab-column connections by means of 4 specimens. The formation and development of inner shear crack were monitored by using a special strain measuring rod during the experiment. The test results showed that the failure pattern of specimens was related to both gravity shear ratio and slab reinforcement ratio; unbalanced moment bearing capacity of the same gravity shear ratio specimens could be improved effectively by increasing reinforcement ratio; the inner shear crack had been generated before punching shear failure happened, and developed from the compression zone nearing the column to the tension zone locating at the bottom of slab. Based on the results in this study and current test data, the calculation method based on eccentric shear stress model which was adopted by GB50010—2010 was compared with the one used by Eurocode2-04, and the reasons for the shortcomings of eccentric shear stress model were analyzed.