Abstract: The joint density, joint inclination angle and joint roughness are the three key factors that control the mechanical response of basalts. Based on the 3D printing technology, the uniaxial compression and interfacial shear tests are carried out to deeply explore the weakening effects of the existence of special columnar joints on the strength and deformation of the basalts according to the failure modes of different columnar jointed basalt samples, and the relationship between the joint factor and the anisotropy effects of samples is analyzed. The research results show that with the increase of the joint factor, the linear reduction degree of the strength reduction coefficient and the exponential relation reduction degree of the modulus reduction coefficient of the simulated columnar jointed basalt samples are significantly affected by the failure mode. The larger the values of the strength anisotropy effects and modulus anisotropy effects, the stronger the weakening effects of columnar joints on basalt blocks. Under different failure modes, the strength anisotropy effects increases linearly with the increase of the joint factor, and the modulus anisotropy effects increase exponentially. The research results can provide some technical support for the anisotropic mechanical response analysis of engineering rock masses.