The soil nail head is the weak point in the overall structure of the soil nail wall. In order to study the anchorage performance of soil nail head, this paper takes an assembled flexible surface GFRP reinforced soil nail wall as an example. Through indoor nail head anchorage performance test and 3D numerical simulation the ultimate tensile strength, nail head deformation and damage pattern of hollow GFRP bar nail head with 32 mm outer diameter were investigated. It was found that the ultimate load bearing capacity of such GFRP bar nail head is between 240 kN and 290 kN. When the nut is tightened, the stress of the thread is mainly distributed in the first three rings of threaded teeth, with significant stress concentration exists at the first ring of threaded teeth in the head of the nail. In addition, a mechanical model of the threaded tooth of the nail head was developed using the thread expansion method, and the relationship between the ultimate shear strength of the first ring thread and the ultimate load on the nail head was derived. The ultimate load-carrying capacity of this GFRP bar nail head was calculated to be 244.54 kN, which is consistent with the test results.The brittle damage characteristics of the indoor nail head anchorage performance test determined that the safety factor of GFRP tendon nail head is between 1.8 and 2.0. It is also determined that the safe load of such GFRP tendons is between 125 kN and 135 kN, providing a reference for the research and application of similar projects.