自发参量下转换(spontaneous parametric down－conversion，SPDC)光场是一种非经典光场，它是由单色泵浦光子流和量子真空噪声对非线性晶体的综合作用而产生的。基于量子理论解释了SPDC光场的产生机理，说明从经典理论如何理解SPDC光场。较全面介绍了SPDC光场的非经典特性及在激光技术、遥感、量子通讯等领域的应用研究进展，展望了它应用研究的发展方向与前景。

Spontaneous parametric down-conversion is a non-classical optical field,which is generated by the interaction on nonlinear crystal of monochromatic flux of pumping photons and quantum vacuum noise. In this paper,the generation mechanism of spdc light field is interpreted by theory of quantum mechanics;the interpretation by classical theory is also given here. The paper also introduces roundly the non-classical characteristics and application advances of spdc light field in laser,remote sensing and quantum communication. Last but not least,SPDC's application prospect and its developing direction are also given in this paper.