对一种激光驱动的微臂机构的运动机理进行分析。该微机械臂的典型长度在亚毫米量级，宽度和厚度在数微米量级。微臂同一个半导体激光器单片集成或混合集成成为一个整体。当激光器输出光脉冲时，微臂将发生振动。文中采用一端固定、一端自由运动的长方形悬臂的力学模型，分析比较了激光的光压作用和激光的热效应两种机理。根据推导出的公式估算，得出了在现有条件下激光驱动的基本机理是光的热效应的结论。对这种微臂的运动特性作了初步的讨论。 The motion mechanism of a laser-driven micro-arm mechanism is analyzed. Typical lengths of the micromechanical arm are on the order of submillimeters, with widths and thicknesses on the order of a few microns. Micro-arm integrated with a semiconductor laser monolithic or hybrid integration as a whole. When the laser output light pulse, the micro-arm will vibrate. In this paper, a mechanical model of a rectangular cantilever with one end fixed and one end freely moved is used to analyze and compare the mechanism of laser pressure and laser thermal effect. According to the deduced formula, the conclusion is drawn that the basic mechanism of laser driving under the existing conditions is the thermal effect of light. The motion characteristics of this kind of arm are discussed preliminarily.