Abstract: Effect of target size and shape for characteristic of target-pointing movement has always been the principle of the button design in human-computer interaction.The subjects react to three different width targets with both square and circle.Through the study of reaction time and accuracy of subjects there are three conclusions：target size and shape can effect the current-control phase of target-pointing movement;squares have better throughput than circles;the reaction time is more sensitive to width with the bigger index of difficulty.The conclusions can be used to instruct the shape and size design of buttons.

Key words: Fitts’ law, target size, target shape, throughput, the index of difficulty, target-pointing movement, Human-Computer Interaction（HCI）

摘要： 触点运动特性是人机交互界面按钮设计的依据。该研究以三种不同目标宽度水平和正方形与圆形两种目标形状为控制变量设计实验。对被试的反应时间和正确率进行分析，结果发现：目标大小和形状对触点运动的影响主要体现在触点运动的趋势控制阶段;正方形目标的操作绩效优于圆形;在难度系数较大时反应时间对目标大小的变化比较灵敏。研究结论对交互界面按钮大小和形状的设计具有一定的指导意义。

关键词: Fiits定理, 目标大小, 目标形状, 操作绩效, 难度系数, 触点运动, 人机交互界面（HCI）, ,