Research on MAC (Media Access Control) layer protocols in wireless ad hoc networks is extensive, but there are evident problems in small-scale network scenarios with few link changes, such as excessively complex protocol design which leads to difficult implementation, high control overhead, low resource utilization and high service delay. In view of this situation, this paper combines competition, election, and reservation mechanisms to design a low signaling overhead multiple access (LSO-MA) protocol for small-scale and relatively stable ad hoc networks. Firstly, the procedures of network establishment and maintenance are optimized to reduce the amount of control resources. Moreover, the two-layer route, queue management, and resource allocation mechanisms are designed. Simulations results show that in small-scale and relatively stable ad hoc net-works, the election period has been shortened by seventy percent, the whole network maintenance period is less than one hundred time slots, the data transmission delay is less than seven milliseconds and the overall resource utilization rate is higher than seventy percent. The proposed protocol can lay a good foundation for MAC layer protocol implementation of small-scale wireless ad hoc networks.