详细综述了银盘 (包括HII区，早B型星，行星状星云和疏散星团) 径向元 素丰度梯度的观测结果，分析了丰度梯度的空间和时间变化情况，指出根据目前 的观测结果，还很难确定在银盘的演化历史中径向元素丰度梯度是逐渐变平缓还 是逐渐变陡。比较了目前各种化学演化模型对径向丰度梯度演化的预测结果，初 步探讨了丰度梯度可能的产生机制及影响其演化的各种重要物理过程。
Detailed summary of the observed abundance gradients along the Galactic disk was presented, including HII regions, early B stars, PN objects and open clusters. Variations of the gradients in space and time were discussed. According to the current observational status, it is not clear whether the abundance gradient is gradually flatten or steepen during the evolution of the Galactic disk. Theoretical predictions for gradients evolutions of various models were presented. The physical processes which result in the gradient and its evolution are explored. The evolution of abundance gradients is found to be very sensitive to the stellar yields，model assumptions on star formation history，infall and also to the relative importance between $SFR$ and infall.