The paper analyzed the properties of concentric curve, theprinciple and method of setting out stakes of middle-line &sidings on one random station and closed with main points.

• 分析了同心曲线的性质，提出了可在任意点设站测设同心曲线的原理及放样同心曲线的中线、侧线各桩并闭合于各自主点的方法.