Density functional theory B3LYP is employed to obtain the optimized geometries of the ground state and interaction energy for triazines and water complexes. The results show that the 1,2,3-triazine-water, 1,2,4-triazine-water and 1,3,5-triazine-water complex on the ground state have Cs, Cs and C1 symmetry, and strong hydrogen bonding interaction with −17.83, −17.38 and −13.55 kJ/mol after basis set superposition error and zero-point vibration energy correction, respectively, and large red-shift for the symmetric H-O stretching vibration frequencies forming N...H-O hydrogen bond in the triazines complex. The first singlet (n, π*) vertical excitation energy of the monomer and the hydrogen bonding complexes between triazines and water is investigated by time-dependent density functional theory.