The calculation of the pullout force of bonded internal anchor head is a key problem in the design of ground anchor engineering. In this paper, a calculation model considering the joint action between anchor, slurry and geotechnical is proposed, and the theoretical solution of the distribution of internal force and force transmission law of anchor head is given, which provides a tool for further analyzing the anchorage characteristics of ground anchor in geotechnical and developing the design method of anchorage engineering.