At present, the problem of children’s education informationization is becoming more and more prominent. With the strengthening of national education, children’s online education has become one of the main forms. In order to educate children online, this paper proposes an online education system based on 5G technology and Internet of Things technology, which mainly solves the problems existing in current education. The results show the following: (1) UI test results basically meet the requirements of users; for the pursuit of personalized users, further development and improvement are needed. (2) Compared with children’s module, the response time of manager module increased by 12%, and all the response times did not exceed 10s, so the user experience was very good. The access success rate of children’s module is 99%, and that of managers’ module is 98%. It is necessary to further study what factors interfere with the success rate, which leads to the failure of 100% success. (3) After optimization, the total energy consumption is the lowest compared with NOMA and TDMA, which is the best energy efficiency optimization method to solve the communication of Internet of Things. The simulation of the system is in good condition, and the follow-up research work of developers will take this system as the core to improve more details, hoping to put it into market operation formally.