Based on the bionic fractal theory, a fractal tree-like photobioreactor (PBR) with high surface area to volume ratio is designed on the basis of bifurcation tree algorithm and manufactured via 3D printing technology. Numerical simulation and experimental results show that the fractal structure has a good flow performance and can lead to secondary flow, which is beneficial to enhance the turbulence and produce smaller bubble sizes. Chlorella culture in the fractal tree-like PBR has a higher Fv/Fm (Chlorophyll fluorescence parameter), close to 0.767, and higher efficiency of photosynthetic growth as well as CO2 capture, compared with multitubular PBR and conventional acrylic column reactors. Therefore, the fractal tree-like PBR can improve the efficiency of light energy utilization and bioreaction. Combined with 3D printing technology, fractal PBR blazes a new trail for process intensification on the microalgae cultivation. (C) 2018 Elsevier Ltd. All rights reserved.