The present work investigates and compares the hydraulic and thermal performances of two tree-like networks with constant surface area constraint and constant volume constraint. The results find that the optimal channel diameter ratio to reach a minimum hydraulic resistance satisfies beta(m) = N-2/5 for the tree-like network with surface area constraint, but beta(m) = N-1/3 for the tree-like network with volume constraint. The convective heat transfer in both of the two tree-like networks with different size constraints is independent on the channel diameter and diameter ratio, but increases with the increasing channel length, channel length ratio, branching level and branching number. For the two tree-like networks with exactly the same channel length, length ratio, branching number and branching level but different channel diameter, the present work provides a segmenting model to choose the network with better hydraulic and thermal performances. (C) 2018 Elsevier Ltd. All rights reserved.