Abstract: This article experimentally and numerically investigates the delamination propagation behavior of T700/QY9511 asymmetric laminates under tensile loading. Five kinds of laminates with different initial delamination positions were designed, and delamination propagation tests based on the double cantilever beam configuration were conducted according to ASTM standard. The results showed that as the distance between the initial pre-crack position and the mid-plane of the specimen increases, the fracture toughness shows a certain downward trend. A finite element model was established using ABAQUS software, and the delamination propagation behavior was simulated using virtual crack closure technique and cohesive zone model. The predicted load displacement responses were in satisfactory agreements with the experimental results. In addition, the distribution pattern of strain energy release rate at the crack front was explored through virtual crack closure technique. The results can provide theoretical support for the design and analysis of asymmetric composite laminates.