Based on the load model of uniform isotropic semi-infinite elastic，we deduced a calculation of vertical displacement and tilt and proposed a method of calculation of vertical displacements and tilts caused by irregular load on the ground or underground at a certain point with two-dimensional and three-dimensional shape． We compared the difference between the simplified model and the irregular model． Finally the vertical displacements near the irregular load and the distribution of horizontal tilt are presented． The results show that，compared with mass simplified model，irregular load model has certain advantages for describing the near field． The establishment of two-dimensional irregular load model can help with the calculation of the modal vector superposition after the load scatter． The three-dimensional irregular load model can redistribute load scatter through different weight given to scatter after the load scatter． and then obtain displacement with the vector calculation method． The results of vector superposition calculation from scattered irregular load both in two dimension and three dimension are all convergent obviously as grids are becoming dense，and it is shown that the calculation method is correct and feasible．