Dibutyltin benzoin benzoyl hydrazone complex I [C₆H₅(O)C=N-N=C(Ph)CH(Ph)O]₂[(n-Bu)₂Sn]₂ and dibutyltin benzoin salicyl hydrazone complex II [2-(OH)-C₆H₄(O)C=N-N=C(Ph)CH(Ph)O]₂[(n-Bu)₂Sn]₂ were synthesized and characterized by IR, ¹H, ¹³C and ¹¹⁹Sn NMR spectra, HRMS, elemental analysis and thermal stability analysis, and the crystal structures were determined by X-ray diffraction. The crystal of complex I belongs to monoclinic system, space group P2₁/n with a = 11.1942(8), b = 10.4754(7), c = 23.6700(17) Å, b = 101.529(2)°, Z = 2, V = 2719.6(3) ų, D_c = 1.371 Mg·m^–3, m(MoKα) = 0.966 mm^–1, F(000) = 1152, R = 0.0458 and wR = 0.1312. The crystal of complex II is of triclinic system, space group P with a = 9.9960(4), b = 11.2466(4), c = 14.0509(5) Å, α = 69.4190(10)°, b = 70.0600(10)°, γ = 81.8090(10)°, Z = 1, V = 1389.69(9) ų, D_c = 1.380 Mg·m^–3, m(MoKα) = 0.950 mm^–1, F(000) = 592, R = 0.0284 and wR = 0.0690. In vitro antitumor activities of both complexes were evaluated by CCK8 method against three human cancer cell lines (MCF7, NCI-H460 and HepG2), and complex II exhibited better antitumor activity than I. The interaction between complexes and calf thymus DNA was studied by UV-vis, fluorescence spectroscopy and viscosity measurements.