The ultimate goal of decision-making of seismic fortification level is to prevent structural collapse and to ensure life safety. The criteria of seismic design level decision-making should be shifted from the principle of uniform hazard which only considers the seismic hazard, to the principle of uniform risk which considers both the site variability of seismic hazard and the uncertainty of seismic collapse capacities of engineering structures. In the newly released 5th-generation Seismic Ground Motion Parameters Zonation Map of China, the fourth level of seismic fortification, i.e., very rare earthquake (VRE), or catastrophic earthquake, has been proposed. However, the principle of three levels of fortification is still used in the current Seismic Design Code of Buildings. Therefore, it is urgent for the current seismic design criteria to transit from the three-level fortification to the four-level fortification. Another problem is that the definitions of the very rare earthquake in different countries are confused. In this paper, the principle of risk-targeted definition of four-level seismic design levels is firstly introduced, and then, an analytical approach to determinate the risk-targeted seismic design levels is put forward. Aiming at the earthquake environments and the seismic fortification situations in mainland of China, the values of target collapse risk, as well as the target conditional collapse probabilities corresponding to very rare earthquake, rare earthquake, and design basis earthquake, are proposed. Using these proposed values and the approximated method for determining the seismic hazard coefficients, the risk-targeted PGA values corresponding to the four seismic design levels are preliminarily calculated. Comparison analysis is conducted between the current seismic design code of buildings, the newest seismic ground motion parameters zonation map, and the existing research results of some Chinese scholars. It is found that the PGA values of very rare earthquake using the proposed method are larger than the ones in the newest seismic ground motion parameters zonation map, while the PGA values of rare earthquake, design basis earthquake and frequent earthquake are smaller than those in the current seismic design code of buildings.