电离氢区（H II区）是年轻恒星形成的场所。这些恒星辐射大量紫外光并电离周围巨分子云中的气体，产生各种谱线。H II区常存在于晚型星系中，研究它们有助于研究星系中恒星的形成和化学性质并进一步了解星系的形成和演化。我们将利用国家天文台2.16米望远镜观测的晚型星系NGC 628中H II区的长缝光谱数据，获得这些区域和星系背景的积分光谱。测量H II区的光谱发射线，并计算谱线的基本性质和分析它们的相关性。搜集金属丰度的各种测量方法,给出一个可靠的金属丰度经验估计公式，并研究星系金属丰度梯度。利用星族合成模型，并结合测光数据，我们还将获取H II区中恒星成分的星族特征以及气体和尘埃的性质，分析恒星和星际介质性质的相关性以及它们之间的内在物理联系。研究影响H II区在发射线诊断图(BPT图)和IRX-β图上分布的各种因素，讨论不同性质H II区的演化状态和尘埃消光特征。

H II regions are the sites where young stars are born. These young stars emit a lot of ultraviolet radiation, ionize the surrounding Hydrogen gas in giant molecule clouds, and generate sorts of spectral lines. H II regions are commonly found in spiral galaxies, so studying them will help to learn the star formation and chemical properties and in advance the formation and evolution of galaxies. We will utilize the long-slit spectroscopic data of a nearby late-type galaxy (NGC 628) from the 2.16m telescope, belonging to the National Astronomical Observatories of China, to obtain the integrated spectra of H II regions and corresponding galactic backgrounds. Spectral properties of the H II regions will be measured and the correlations among them will also be explored. We will collect the methods to estimate the metal abundance, provide a reliable and robust empirical formula, and study the abundance gradient of the galaxy. Combining stellar population synthesis models with photometric data, the stellar population properties in H II regions and the properties of gas and dust will be obtained. We will analyze the relations between the properties of the stellar content and those of the interstellar medium and the intrinsic physical connections between these two compositions. The factors that affect the distributions of H II regions on the emission line diagnostics (BPT diagram) and IRX-βdiagram will be investigated in order to discuss the evolution status and extinction characteristics of dust in different H II regions.