The invention relates to a rapid navigation channel model modeling method for 3D printing. The method comprises steps that initial terrain data of the engineering river section including the terrain elevation is collected; a model making scope is determined; abnormal data of the initial terrain data is excluded; the model both-side flat top elevation is determined; the model both-side flat top elevation is utilized to replace the shore elevation; the model bottom elevation is determined; model boundary control point data is integrated; discrete processing is carried out; a navigation channel model is generated, the model is cut into a plurality of channel model blocks, and the model blocks are outputted and printed. The method is advantaged in that a digital model which can be identified by a 3D printer can be rapidly established for any complex river terrains, and the river terrain model can be guaranteed to have the relatively high similarity to the prototype.