Abstract: An uniaxial compression test was conducted for T-stiffened composite curved panels which were automatic fiber placement (AFP) manufactured or hand-laid. A 3D optical measurement method which was based on the digital image correlation (DIC) was used to monitor the local buckling and post-buckling, and the results were compared with that of strain gauges and displacement transducers. The results show that the displacement field can be accurately captured by DIC, and the buckling mode observed using DIC is consistent with that the values of the strain gauges reflect. Different from the conventional method of strain gauges, the whole progress of the buckling mode transition of the skin caused by the secondary instability is accurately captured by DIC. The buckling modes at different times (i.e. different load levels) are clearly and intuitively observed using DIC equipment, so the buckling load of the structure is easy to determine and the error is less than 5% compared with the load indicating the strain-load curves separation. A numerical simulation analysis based on finite element software ABAQUS was carried out. The computation results were compared with the test results, revealing that there is a good consistency among the computational results, results from DIC and results of conventional method.