The article deals with analysis of transfer mechanism of the force from composite bolt to rock surroundings. The ultimate capacity of anchoring member depends on relatively wide range of input parameters. Moreover, the range of parameters of rock mass changes. The axisymmetric FEM of problem was constructed in Plaxis2D. The Mohr-Coulomb failure criterion, described by equivalent rock strength parameters determined by fitting an average linear relationship to the curve representing Hoek-Brown failure criterion, was used. Later, statistical analysis based on the design of experiment concept and the Response Surface Method (RSM) was carried out. The result of the full-factorial design and RSM analysis provide the regression model. It describes dependence of the bolt ultimate capacity Fy and corresponding deformation uy on the uniaxial compressive strength and Rock Quality Designation RQD. Results show that RQD starts to have significant impact on the Fy from the level of σc above approx. 80 MPa. The deformation uy is affected by the RQD conversely.