The invention relates to a preparation method of a columnar jointed rock mass sample containing unfilled blind joints. The preparation method comprises the following steps: simulating the structure and the form of blind joints in an actual columnar jointed rock mass, and determining 3D (Three-Dimensional) digital space models of various blind joints in the columnar jointed rock mass sample; three-dimensionally printing the SD space models of the different types of blind joints by adopting a water-soluble material, thus obtaining different types of blind joint simulation components, and coating the surfaces of the obtained blind joint simulation components with hot melt glue; preparing cement mortar to simulate the actual columnar jointed rock mass, mixing and stirring the blind joint simulation components with the cement mortar, pouring a mixture into a mold, and curing until forming a sample component; demoulding; carrying out baking, water saturation, drying, curing and machining treatment on the demoulded sample component, thus obtaining the columnar jointed rock mass sample. According to the preparation method disclosed by the invention, a 3D printing technology is used for preparing the blind joint simulation components, so that the form and the structure of the blind joints are accurately controlled; the water-soluble material is adopted for preparing the blind joint simulation components, so that the problem that a component for simulating the blind joints cannot be taken out is solved during sample preparation.