A testing system of a liquid crystal display panel including a substrate, a driving circuit, a first testing pad, and a second testing pad is provided. The substrate includes a pixel array whose one side has a pixel testing area. The driving circuit is formed on the substrate and connected to the other side of the pixel testing area for providing a signal to the pixel array. The first testing pad is connected to the driving circuit. The second testing pad is connected to the pixel testing area. The testing method of the liquid crystal display panel includes: respectively testing whether the liquid crystal display panel and the pixel testing area have a defect and accordingly generating a first testing pattern and a second testing pattern; combining the first testing pattern and the second testing pattern to determine whether the defect occurs at the driving circuit or the pixel array.