The concept of virtual linkage simulation was put forward to solve the problems of using physical PLC for virtual simulation of equipments and inability to inspect rationality of PLC program in the completion of research and design. Virtual devices and virtual PLC runtime environment was constructed using high-level language real-time transmission and signal processing between virtual PLC and virtual devices. The operation and fault information in the virtual scene was manifested. Ultimately, virtual simulation on mechanical equipments not depending physical PLC was realized. The virtual linkage simulation can also test the rationality of PLC program, which expands the new ideas of virtual simulation. The necessity and feasibility of virtual linkage simulation technology was discussed with an example of printing machine control simulation.