Abstract: On the basis of the established biogrout model for loess with joints, numerical modeling and solution are carried out by means of the finite element simulation software COMSOL.Considering the initial urease activity, cement concentration and joint aperture, the filling rates of joints and porosity aswellas the effective reinforced area of loess mass under three grouting factors are calculated and analyzed.The reinforcement effect of join-loess mass is studied.The results show that the initial urease activity is an important factor affecting the grouting effect.For the concentration of cement liquid, in order to consider the reinforcement effect and to reduce the amount of waste liquid at the same time, the appropriate concentration of cement liquid should be selected.The effect of joint aperture on the depth of reinforcement is more obvious, which is consistent with the law of water infiltration for the joints.The comprehensive analysis of the three grouting factors shows that the reinforced effect of loess with joints at a limited depth from the grouting port is better, and the grouting uniformity needs to be improved.