化学还原法是制备金纳米粒子的常用方法之一。本文采用液相合成法，选择不同的还原剂并通过调整还原剂与氯金酸的摩尔量比例，合成了不同形貌大小的金纳米粒子，并使用紫外-可见吸收光谱仪和透射电子显微镜对所得粒子的光学性质、形貌及粒径分布进行了表征。实验中成功制备出了三类不同形貌大小的金纳米粒子，它们的紫外-可见吸收光谱图均显示出明显的等离激元吸收。TEM测试结果表明，制备出的三种金纳米粒子粒径大小分别为：(8.89±2.44) nm，(12.73±1.16) nm，(21.54±3.11) nm。总体而言，对比本文中所涉及到的几种还原剂，柠檬酸钠的效果最好，最终所得的金纳米粒子质量高，具有形貌均一、尺寸分布窄、稳定性好等优点。同时发现，通过控制柠檬酸钠与氯金酸的比例，可制备得到不同尺寸大小的金纳米粒子；在pH大约为6.4的条件下，金纳米粒子的粒径随着柠檬酸钠与氯金酸比例的增大而增大。

The chemical reduction method is one of the mostly used methods for preparing gold nanoparticles. In this work, solution phase synthesis method was used to synthesize gold nanoparticles with different morphology and size, through adopting various reducing agents or by controlling the molar ratio of reducing agent to chloroauric acid. UV-vis absorption spectrometer and transmission electron microscope (TEM) were used to determine the optical properties, morphology and particle size distribution of obtained particles, respectively. Three kinds of gold nanoparticles with different morphology and size were successfully synthesized in this thesis, displaying typical plasmonic absorption characteristics as telling from UV-Vis absorption spectra. TEM results show that the size of these three gold nanoparticles is: (8.89±2.44)，(12.73±1.16)，(21.54±3.11) nm, respectively. In conclusion, sodium citrate is superior to the other reducing agents as the obtained gold nanoparticles are of high quality. It was found that the size of gold nanoparticles increases as the ratio of sodium citrate to chloroauric acid increases.