【目的】 为明确豌豆蚜Acyrthosiphon pisum虫龄的鉴别特征，以期达到准确快速识别豌豆蚜龄期的目的。【方法】 采用显微成像技术观察并测定不同翅型、不同虫龄个体的体长、体宽、头宽、腹管长度、尾片长度、触角长度和后足胫节长度7项指标。【结果】 不同龄期豌豆蚜形态特征存在差异，无翅型与有翅型个体的腹管长度在各龄期间均无重叠，可作为豌豆蚜龄期鉴定的重要指标。后足胫节和触角长度，可以作为龄期划分的辅助指标。此外，触角节数可以用来区分1龄和2龄若蚜，翅基发育程度可以用来区分有翅型豌豆蚜3龄与4龄，尾片的发育程度可作为区分若蚜与成蚜的典型形态特征。【结论】 以个体的腹管长度作为豌豆蚜龄期鉴定的主要指标，配合后足胫节长、触角长度、触角节数、尾片与翅基的发育程度，可达到快速鉴定豌豆蚜各个龄期的目的。

[Objectives]  The objective of this research was to identify morphological characteristics that can accurately distinguish the instars of Acyrthosiphon pisum. [Methods]  Seven morphological indices of winged and wingless morphs, including body length, body width, head width, cornicle length, cauda length, antenna length, number of antennal segments and hind tibia length, were measured under an ultra-wide area, 3D microscope. [Results]  Although the morphological characteristics measured differed among both wingless and winged instars contiguous instars overlapped in all except cornicle length, which was therefore the only morphological characteristic that could reliably distinguish different instars. Hind tibia and antenna length are, however, useful as auxiliary characteristics. Additionally, the number of antennal segments can be used to differentiate between 1st and 2nd instar nymphs, and cauda shape to differentiate between nymphs and adults. [Conclusion]  The instars of A. pisum can be accurately and quickly identified on the basis of cornicle length. Hind tibia length, the number of antennae and degree of cauda development also facilitate distinguishing the instars of this species.