With the development of information technology, smart devices such as personal computers, smartphones and VR headsets are becoming more and more popular in modern society, and interactive communication with these smart devices has become an essential part of people’s daily life. Many people will use multiple devices to accomplish a same task, and this behavior brings certain challenges to multi-device application design. Designers need to make applications that provide an appropriate and consistent user experience across devices in response to the characteristics of these devices. However, existing research on multi-device user experience lacks a generally accepted approach to consistent design. In addition, most of the existing research has focused on how to maintain consistency between mobile and PC. With the rapid development of VR technology, VR has been widely used in many fields. The design approach for VR applications is very different from the traditional 2D screen-based design, thus how to maintain the consistency between VR and other devices is an urgent problem to be solved.
　　In this paper, after investigating the theories of consistency of multi-device application experience, we propose a set of consistency target framework for multi-device design contexts. The framework mainly contains four levels: “semantic consistency”, “syntactic consistency”, “perceptual consistency” and “lexical consistency”. Based on this framework, a design process and the corresponding design methods are proposed to guide the multi-device consistency design practice. The specific design methods include “constraint-based design” and “highway-based design”.
　　Based on this design process, the design practice is carried out for the serious game “Virtual Experiment of Film Language” with the goal of consistent user experience on multiple devices. We designed and developed prototypes of VR, PC and mobile versions of this serious game. Based on the consistency target framework, the design consideration under each consistency level is elaborated, and the interaction optimization for VR in this case is discussed in detail. Finally, a multi-device consistency evaluation for this serious game was conducted through an experiment. The experiment recruited 20 participants to experience the VR, PC and mobile versions of “Virtual Experiment of Film Language”. The experimental results show that the consistency of the multi-device experience of this serious game meets the expected requirements. The results of this experiment further demonstrate the effectiveness of the consistency target framework and the design process proposed in this paper. This target framework and design process can help designers to design application that target multi-device consistency and improve usability and user experience.