串行法则是一套用于有机化学的规则，用来命名有机分子的立体异构现象。一个有机分子可能含有多个立体中心和双键，而每一个都给了这个分子两种可能的组态。这个规则的目的是给予立体中心R/S标记，双键E/Z标记，而使每个组态都可以用系统性的语言来描述。

串行法则和其他的命名原则，如IUPAC命名法有显著的不同，原因是此规则是被制定来命名有立体异构物的分子，而不是来一般的分类与描述化合物。

使用串行法则的步骤通常是：

The Cahn–Ingold–Prelog (CIP) sequence rules, named for organic chemists R.S. Cahn, C.K. Ingold, and V. Prelog—alternatively termed the CIP priority rules, system, or conventions—are a standard process used in organic chemistry to completely and unequivocally name a stereoisomer of a molecule. The purpose of the CIP system is to assign an R or S descriptor to each stereocenter and an E or Z descriptor to each double bond so that the configuration of the entire molecule can be specified uniquely by including the descriptors in its systematic name. A molecule may contain any number of stereocenters and any number of double bonds, and each usually gives rise to two possible isomers. (A molecule with an integer describing the number of its stereogenic centers will usually have stereoisomers, diastereomers each having an associated pair of enantiomers. The CIP sequence rules contribute to the precise naming of every stereoisomer of every organic and organometallic molecule with all atoms of ligancy of fewer than 4 (but including ligancy of 6 as well, this term referring to the "number of neighboring atoms" bonded to a center).