Abstract: Abstract A rational approach to formulate Mindlin triangular element is proposed in this paper. Firstly, the variation functions of rotation and shear strain along each side of the element are determined based on the Timoshenko beam theory. Secondly, the rotation, curvature and shear strain fields in the domain of the element are determined with improved interpolation. The resulting element is free of shear locking in the case of thin plates. Numerical examples show that the element, called TMT, is a high-performance element for thick and thin plates.