Flowchart is a common graphical representation of a process or step-by-step solution for a problem simply drawn in the software design stage. A flowchart helps visualize how an algorithm works to solve a problem better than the program source code. However, it is crucial and beneficial to validate the correct behavior of the flowchart automatically using the formal methods. In this paper, we propose a scheme of transforming a basic flowchart into a coloured Petri net so that the designated model could be validated beforehand. A set of mapping rules is proposed to construct the resulting coloured Petri net from a given flowchart. The basic data types, including integer, boolean, and string, are coped in order to simulate the changing of state of variables in the flowchart. The resulting coloured Petri net are simulated and verified to ensure the correctness of its behavior using CPN tools.