Business process modelling has been widely applied by many companies to support the projects such as BPR or enterprize integration. In general, business modelling technique plays the role of pre-designing and evaluating the business flow before the final implementation. However, due to certain improper situations, the developed model might not be appropriate for the final analysis and evaluation. Therefore, model feasibility should be confirmed before the formal evaluation. This research proposed a Petri-net-based approach to evaluate the feasibility of a model defined by BPMN (business process modelling notation). Two kinds of invalid situations, deadlock and infinite loops, will be defined and analysed. There are four phases in the proposed approach. In problem analysis phase, a modified business process development approach would be proposed first. Then, the invalid model would be defined and classification. In the design stage, the developed BPMN model will be transferred to Modified BPEL4WS, which is an XML based language. By applying XSLT and Java, the transferred BPEL4WS will be translated to a Petri-net model specified as CPNXML (Colored Petri-net XML). In the simulation phase, the CPNXML file can be imported into a graphical simulation package CPN Tools for further analysis. Finally, in the implementation phase, the three kinds of property analysis (deadlock, infinite loops and execution time) will be evaluated in terms of the 'liveness', 'reachability' and 'consumed time' of the converted Petri net model.