This article describes the theory of Poisson Distribution (PD).The PD datas of computer simulation are to approximate Normal Distribution (ND) by Kolmogorov-Smirnov goodness of fit test. Examples are given to illustrate the applications of Poisson Model (PM) to the Multiple-Attempt, Single-Item Tests (MASI) of psychomotor test. It emphasizes that the PD is more suitable than the ND for the fixed-time period of MASI, especially when the μ is small.