Rotavirus is the leading pathogen for acute gastroenteritis in mammals and birds. Although the reverse genetics system has been utilized in many viruses, the system using a helper virus was developed for rotavirus in 2006. As a step for antigenic analysis of VP4 antigen of rotavirus, we prepared an infectious rotavirus with a spike protein VP4 having an antigenic mosaic by substituting one of the cross-reactive neutralization epitopes of a simian strain SA-11 with the corresponding one of a human strain DS-1. The future improvement and application of the rotavirus reverse genetics were discussed in this review.