Abstract: In this paper, a simple approach to formulating a triangular element for the analysis of thick and thin plates is proposed. Firstly, a 9-DOF thin plate element is formulated based on the generalized compatibility condition. Secondly, the shear strain and supplementary deflection fields in the domain of the element are determined using an improved interpolation method and the generalized compatibility condition, respectively. As the plate becomes progressively thinner, the shear strain and supplementary deflection fields approach zero automatically, and the element is free of shear locking. Numerical examples show that the element, GCLLM-T9, has a higher precision for a large range of thickness-span ratio from very thin plate to thick plate.