Real pets function as companions in human life and most owners believe that pets are family members or friends. However, real pets have problems of cleaning, care, nurturing space constraints, and other issues while the artificial companion, which has real pet function and can be substituted for real pets. The purpose of the study is to find out the design direction, understand the technical and functional changes of artificial companions, as well as the needs of users. The study analyzes the evolution of artificial companions from relevant literature, STS studies, and Need-hierarchy theory, and then infers the developmental trends to help designers develop new products. Finally, the evolution process is divided into five phases: Real interaction→ Imagine driving→ Mimicry of reality→ Multiple activity→ Intellectual interaction. The study also concludes that the developmental trends of artificial companions point towards the online virtual pet, and the online virtual pet will emphasize the self-expression and the social interaction on the Internet.