We study theoretically the quantum effects of the littlest Higgs model (LH) mediated by flavor changing one-loop Feynman diagrams on the rare decay process t→cH⁰. The comparison of the decay width in the LH model with that in the standard model (SM) is made. We find that the decay branch ratio of t→cH⁰ in the LH model is at most of the order ～10^-12, which is two order larger than in the SM. The numerical results show that the difference between the branch ratios in the LH model and the SM is generally sensitive to the LH model parameters, such as symmetry breaking scale f, Higgs boson mass m_H⁰, and x=v'4f/v² in our chosen parameter space, but relatively insensitive to the value choice of the cosine of the mixing angle c and the ratio λ₁/λ₂.