We present a high‐resolution low‐energy electron diffraction study of the clean Pt(110) reconstructed (1×2) to (1×1) phase transition and its critical phenomena. The phase transition is shown to be a continuous order–disorder type with critical temperature Tc∼960 K. The critical exponents β, γ and ν extracted from the (0 (1)/(2) ) superlattice beam are consistent with the 2D Ising class. The observed critical scattering maximizes around Tc and is limited by the finite size of the (1×2) ordered region. The line shape of the (0 (1)/(2) ) beam can be described by a power Lorentzian with decreasing power m as T→Tc. At T>Tc, where only the short‐range ordering exists, the structure factor of the superlattice, represented by the (0 (1)/(2) ) beam, shows scaling and isotropic behavior even though the broadening along the [11̄0] and the [001] directions is anisotropic. The scaling function can be well fitted by either Fisher and Burford's form or a Lorentzian.