植物解剖学主要是研究植物的内部构造，通常是现生植物，从而可以了解植物体各部之功能。

植物是高度演化，其结构上及功能上的特化，于植株外部反应了其身体的分化，在内部则反应于不同类别的细胞、组织、组织系统、器官等。

早期的植物解剖学被涵纳在描述植物的外形及外部构造的植物形态学之中，大约在20世纪中期方被考虑为一独立的学门，具有专门的研究领域，并被认为是专门研究植物内部构造的科学。现代的植物解剖学经常是细胞层级的显微构造，即组织切片、显微镜学相关议题等。

Plant anatomy or phytotomy is the general term for the study of the internal structure of plants. While originally it included plant morphology, which is the description of the physical form and external structure of plants, since the mid-20th century the investigations of plant anatomy are considered a separate, distinct field, and plant anatomy refers to just the internal plant structures. Plant anatomy is now frequently investigated at the cellular level, and often involves the sectioning of tissues and microscopy.