The design of wing connection joint is one of the major parts in an aircraft design. The quality of the joints plays an important role in the safe operation and performance of an aircraft. Based on the center- outer wing connection joint design of foreign advanced civil aircrafts, two joint specimens were designed for composite wing lower panels. The bear strength and failure mode of joint specimens were studied. The failure process of the flange/skin interface was simulated by using the cohesive element in the commercial software ABAQUS. The research results indicated the debonding starting position of different joint specimens. The bearing capacity of joint specimens under tensile load and the bear strength of bolts were also researched. Finally an effective method was suggested for the design of composite key connection areas after comparing the ultimate failure mode.