By using the tight-binding Hamiltonian and non-equilibrium Green's function methods, the Seebeck and Nernst effects ofα-T3lattice are investigated, in which the lattice interpolates between graphene and the dice lattice via the parameterα. Forα= 0 (graphene), flat bands are always present in the band structure. The Seebeck and Nernst coefficients are consistent with those in graphene. Whenαis non-zero at zero magnetic field, the Seebeck coefficient is an odd function of the Fermi energy. It produces a very large and wide first peak within the band gap for the zigzag boundary. Under the influence of magnetic fields, the first peak of the Seebeck coefficient in the gap region increases withαincreasing. The Nernst effect occurs under the influence of a magnetic field. The height of the zeroth peak of the Nernst coefficient increases withαincreasing. Whenαreaches a certain value, the zeroth peak splits. The post-split peak decreases withαincreasing for the zigzag boundary, but continues to become wider and higher for the armchair boundary.