Systemic vulnerability is an internal and essential factor that influences environmental sustainable development capability. Optimizing adjustments on systemic vulnerability significantly contributes to improved function, decreased disturbance, and guaranteed scientific evolution of environmental sustainable development capability. The connotation of systemic vulnerability of environmental sustainable development capability is defined and demonstrated. Measuring indexes, which reflect three aspects such as economic, ecological, and social subsystems, are established. With the application of the entropy-topsis model, statistical data from 1993 to 2012 in China are collected to carry out empirical research. The measuring values on systemic vulnerability are significantly below the standard values. On the basis of further analysis, adjustment strategy can be constituted for decreasing systemic vulnerability and improving environmentally sustainable development capability.