In internet of things, the design of multiuser access system will meet great challenges. In this paper, a two-dimensional fountain system of multiuser access and SLT coding is presented based on the existing system. First of all, each user's original information is encoded by SLT codes on the time layer, and then each user competes for transmission according to the access probability on the user layer to form a two-dimensional fountain. The system makes full use of fountain codes to effectively improve the signal anti-interference ability. Secondly, for each user using SLT codes, we can simply employ the belief propagation decoding algorithm to decode. Simulation results show that compared with the existing multiuser access system, the proposed system can significantly achieve better throughput performance and solve the problem that the performance of the existing system decoding algorithm has a sharp decline in the higher access probability, so then can provide more users with the opportunity of information transmission which has good practicability in multiuser data transmission.