This study aims to investigate the intrinsic deformation analysis of Iran plateau, using repeated GPS observations scatered across the country. Specificly, the deformation tensors of the first (strain tensor) and the second kind (tensor of change of curvature), as well as their corresponding invariants are obtained. The invariants of the strain tensor are dilatation and maximum shear, which account the horizontal deformation of the actual topographic surafce of the Earth and the invariants of the second deformation tensor are Guassian and mean curvatures which reveal the vertical movement of the crust, namely the uplift and rising regions.This approach keeps the simplicity of computations in a 2-dimensional curvilinear space, while it includes both horizontal and vertical deformations as well, and moreover it referes to the real topographic surface of the Earth.The mathematical representation of the topographic surface of the Earth is derived by interpolation of geodetic heights above reference ellipsoid, determined from GPS observations and the deformation tensors are computed in the Gaussian moving frame attached to this surface. In this study, the suitable shape functions, based on finite element discretization equipped with C1 cubic Bezier interpolant is used to mimic the mathematical form of the topography, by interpolation of its discret shape, avialabe from geodetic height observations. Such interpolation should also be applied for three dimensional displacement fields derived from GPS observations, after they are transformed into Gaussian coordinate system, to enable the evaluation of displacement derivatives required in computation of the deformation tensors.Some graphical representations are used to demonstrate the deformation patterns within the Iran plateau and they are compared with the tectonic features and seismicity map of this region. The results of strain anslysis reveal that the most parts of the network have been contracted with the maximum value of −9.97×10−6yr-1 and the maximum amount of shear strain has been in a rage of 3.67×10−6yr-1 which is occurred in the North part of Iran. Also moving from the northern and central regions of the network to other parts, it is observed that the maximum shear, decreases with a constant rate. Vertical deformation analysis shows that the signs of mean and Gaussian curvatures are respectively negative and positive. This fact elucidates that the Iran plateau has been undergo a subsidence in its most part. Land subsidence can be caused by natural geological phenomena such as earthquake, melting of ices, slow motion of the Earth’s crust and lava exiting from solid crust of the Earth, or human activities such as mining, extraction of underground fluids including underground water, oil and gas.