The invention discloses a preparation method of an internal combustion engine tail gas purifier based on a 3D printing technology. The preparation method comprises the following steps that S1, raw materials are prepared, specifically, ingot casting and melting are carried on required metal raw materials, and corresponding alloy is added into molten metal according to the actual requirements of a honeycomb carrier of the internal combustion engine tail gas purifier; S2, the raw materials are subjected to vacuum atomization powder preparation, specifically, the molten metal is prepared into metal powder through a vacuum atomization powder preparation method; S3, the honeycomb carrier of the internal combustion engine tail gas purifier is prepared; and S4, polishing finishing and acid pickling are conducted. Compared with an existing preparation method, the preparation method of the internal combustion engine tail gas purifier based on the 3D printing technology is simple in technologicalprocess, the finished product composition material is uniform, the product yield is high, the procedures of heat treatment, hot rolling, cold rolling and welding in an existing preparation method areomitted, the risk of product scrapping is reduced, short-process green and clean manufacturing is achieved, and energy is also saved.