The rate of percutaneous absorption of micro-particles is very important due to its effects on human health. In this study, a new approach is proposed to investigate both the lateral and the longitudinal diffusions during the absorption of a micro-particle. The results of the current 2D model are compared with the results of a previous 1D model. According to the results, the influence of lateral diffusion on the rate of percutaneous absorption is important, especially for the lipohilic materials. On the other words, the difference between the results of the two models is more significant, at lower values of the ratio of viable-epidermis-diffusivity to the stratum-corneum-diffusivity (D-VE/D-SC), or at lower values of the viable epidermis to the stratum corneum partition-coefficient (k(VE)/k(SC)). For instance, when D-VE/D-SC equals to 1 and k(VE)/k(SC) is 0.33, for a particle with a radius of 10 mu m, the steady-state-molar-flux estimated by the 2D model is 2.37 times greater than that estimated by the 1D model. Hence, the lateral diffusion should be taken into account in the percutaneous absorption of micro-particles.