Aerenchyma is a collection of air chambers or cavities within the parenchyma of plants. It is essential for the air exportation in aquatic and wetland plants. In this experiment, submerged macrophyte Potamogeton perfoliatus was used as material to observe the longitudinal section and transverse section of the stem via paraffin sectioning technology, the aerenchyma development process of stems and leaves were analyzed in time and space. The results demonstrate that: (1) the structure of the stem includes epidermis, cortex and vascular cylinders. Welldeveloped aerenchyma exists between the endodermis and epidermis. Stem aerenchyma forms about 0.6 mm from the stem apex and matures at about 2.4 mm. (2) The leaf consists of epidermis, cortical parenchyma cells and vascular cylinders. Leaf aerenchyma forms in the second to third neonatal leaves near the stemapex and only forms in the main vein. (3) The stem and leaf aerenchyma development processes are similar, closely spaced clusters of cells initially, then small intercellular spaces appear with the division of the cortical cells, and the subsequent expansion process of the lacuna involves the cell growth and division and cell degradation, ultimately, developed aerenchymaformed. (4) The aerenchyma development process was divided into four phases: solid phase, formation phase, expansion phase, and maturity phase. The development degree of stem aerenchyma varies widely in different phases, the porosity rates in the solid phase, the formation phase, the expansion phase, and the maturity phase are 0.54%, 10.90%, 27.61%, and 57.58%, respectively. However, the node aerenchyma is not welldeveloped and the porosity is only 3.62% at maturity.