The invention relates to a method for detecting saturability of an AGM storage battery. An AGM storage battery after formation is taken, a bottom hole is drilled in the bottom of a single unit of a to-be-detected storage battery, and a bottom hole plug covers the bottom hole; the to-be-detected storage battery is placed at a battery bracket of a swinging device, overturning and acid dripping are carried out by three times, a total acid dripping amount V of the three-times operations is recoded, wherein the V is the sum of V1, V2, and V3; an volume V4 of acid liquor flowing out of the storage battery is recorded; and an actual saturability W of the single unit of the detected storage battery is determined based on a formula: W=100%-(V-V4)/n*100. According to the invention, the actual saturability of the AGM storage battery after formation can be measured accurately and is used as the base of electrolyte adding during the production process of the AGM battery; problems that the battery start-up capability is reduced, the service life is shortened, and the thermal out-of-control phenomenon occurs because of the saturability problem of the battery are solved. Besides, the measurement result also can provide the accurate reference data for the AGM storage battery design process to correct the theoretical calculation value of the AGM storage battery saturability.