The cutterhead is the key component of fullface hard rock tunnel boring machine（TBM）. The layout of the disc cutters is the key process in design of TBM cutterhead, which directly influences the cutterhead performance. Based on two kinds of disc cutter layout schemes for TBM, the influence of different layouts of disc cutter on the mechanical properties of TBM cutterhead is analyzed. From the aspect of the overall force balance of disc cutter, the radial unbalance force and overturning moment of the disc cutter group of the two schemes are compared. From the aspect of local deformation and stress distribution of the cutterhead, a new evaluation index of the cutter distribution density is proposed, and the correlation analysis is carried out with the finite element calculation results of the cutterhead. The study results show that: 1）The disc cutter distribution density is an effective index to evaluate the quality of the cutter layout. 2）The supporting ribs affect the cutterhead mechanical performance significantly. 3）Stochastic layout pattern of disc cutter is better than the doublecrosstyped layout pattern.