Mobile application technology has been gradually applied in the electric power industry. In recent years, a power generation group built a modular unified mobile platform in accordance with the mobile portal model in dual-network isolation environment. The standard functions are mainly used by the group headquarters, and some general functions can also be used by subcompanies. On this basis, this study, based on 4G and Wi-Fi wireless network, hybrid mobile development technology, Nginx reverse proxy technology, SSL VPN, gap and so on, designs a group level mobile platform with unified standard which can support two-level applications and can be flexiblely adapted to the local business needs of each subcompany. Seamless handover is implemented. It provides a reference for the construction of a group level mobile platform which supporting two-level applications in dual-network isolation environment.