Abstract: A 3D printing method employing an adaptive internal supporting structure, involving the steps of: S1—extracting images from a reference biological structure picture to obtain a multi-layer grid texture serving as a plurality of layer pictures for an internal supporting structure of a 3D model; S2—separating multi-layer structures of the model layer-by-layer, and performing binarization and hollowing processing on each layer to obtain a plurality of images; S3—merging each layer picture obtained in step S1 with a corresponding image obtained in step S2 to obtain a plurality of final slice layer structures; S4—determining a support region of the supporting structure in each slice layer according to strength requirements; S5—analyzing the model to perform adaptive structural design and adjusting its strength-material ratio; and S6—restoring the model by using a 3D reconstruction algorithm and printing the model.