Precursor-reforming strategy induced graphitic carbon nitride (g-C3N4) with different morphologies for enhanced photocatalytic hydrogen (H-2) evolution activity is highly desirable. Herein, g-C3N4 microtubes (mg-C3N4) with adjustable closure degree of microtube orifice and spatial anisotropic charge separation are established by conquering hydrogen bond during thermally exfoliate precursor. Compared to the bulk g-C3N4 (bg-C3N4) and ultrathin g-C3N4 (ug-C3N4), the tubular structure endows mg-C3N4 with spatial anisotropic charge separation that accelerates transfer of charge carriers. As expected, the photocatalytic H-2 evolution (PHE) activity of mg-C3N4 has been obviously enhanced. Particularly, the mg-C3N4-24 shows the best PHE activity (957.9 mu mol h(-1) g(-1)), which is over 18.72 and 3.77 times higher than the bg-C3N4 and ug-C3N4, respectively. In addition, selective photo-deposition experiment results reveal a charge carriers migration behavior that photoproduction electrons migrate to the outer shell and holes prefer to move onto the inner shell of mg-C3N4, thus achieving efficient spatial anisotropic charge separation. We firmly believe that the work presents significant advancement for the design of other materials by precursor-reforming strategy. (C) 2019 Published by Elsevier Inc.