Abstract: In view of the deficiencies of low-efficiency and poor mechanical response of columnar joint existing in the physical model tests on irregular columnar jointed rock mass, a one-shot moulding method for preparing artificial irregular columnar jointed rock mass specimens is proposed based on the Voronoi diagram random simulation and the 3D printing technology. Then brittle green wax is used as the 3D printing material to print the irregular columnar joint network, and the irregular columnar jointed rock mass specimens are prepared. Then uniaxial compression tests are performed on the above specimens, and the uniaxial compressive strength, deformation modulus and failure morphology of the specimens are obtained. On this basis, the mechanical anisotropy characteristics and typical failure modes under uniaxial compression are analyzed. Furthermore, the above experimental results are compared with the existing model test ones. It is shown that the proposed one-shot moulding method can improve the efficiency of sample preparation and simulate the mechanical response of real columnar joints very well.