Based on numerous papers on automatic seedling classification (ASC), the seedling grading theory, traditional grading methods, the background and the proceeding of ASC techniques are described.

• 本文在对目前苗木自动分级文献理解和综合的基础上，首先通过对苗木分级技术和分级理论的研究，揭示了自动分级技术的发展背景和理论基础。