Micro-shield machine has complex mechanical properties of the cutterhead tunneling in the complex geological conditions, which puts forward higher requirements on the arrangement of cutterhead structure. Aiming at the typical coastal composite stratum, the cutterhead with a diameter of 600 mm was selected, and the rock breaking model of disc cutters was established based on the principle of dual hobs to collaborate with the rock. Moreover, the dynamic simulation model of the whole cutterhead cutting soil was established according to different cutter layout methods, and three working conditions were considered to analyze the stress and strain of the optimized structure of the cutterhead. The results indicate that the rolling force had the lowest value when the disc cutters spacing was 8 mm, and the rock breaking efficiency was the highest at this time. The cutterheads of Archimedes spiral and single Fermat spiral method could meet the requirements of full excavation of the face, and there was an incomplete cutting phenomenon between the cutterhead cutters of the concentric circular cutter method. However, the maximum and average thrust and torque during the excavation process of the cutterhead of the single Fermat spiral arrangement method were smaller, which was the optimal cutterhead structure. In terms of the cutterhead structure of the single Fermat spiral line knife method, the strength and stiffness check calculation results under the three working conditions all fulfilled the requirements of general mechanical utilization.The research is of reference significance for the optimization design of the cutterhead of the micro shield machine in such projects as pipeline digging.