斗姆，也作斗母，主要是指北斗之母。作為道教的女性神祇，其形象卻是道教眾神中少見的多頭多臂形象，本文以這一形象的來源、特徵及其相關背景為主要探討內容。首先通過對現存明清時期主要圖像材料的考察，歸納了其形象演變的階段性特點；同時通過梳理和分析斗姆的相關經文，論述了斗姆信仰存在著發展與演變的過程，而其多頭多臂形象主要是在其被納入到道教雷法中時，因與密教摩利支天相結合而借用了摩利支天的忿怒相所致，但在借用摩利支天形象時，根據其自身的信仰內涵對所借用的形象予以了調整，使斗姆這一借用自密教菩薩的形象又具有著自身的獨有特徵。本文進一步就斗姆形象中最為突出的特徵的內涵、其借用密教摩利支天形象的主要原因等進行了探討。

Doumu, the Mother of the Dipper, is a Daoist female deity, but she has an unusual image among all of the Daoist female deities, for she often appears as an esoteric Budhisattva who has three heads and six or eight arms. This paper examines the extant image materials of Doumu of the Ming and Qing dynasties and generalizes their traits in different periods, on one hand, and analyzes the distinct contents of related scriptures of Doumu, on the other. It demonstrates that the esoteric image of Doumu derived from Marici, a goddess of light in Esoteric Buddhism, as Doumu was absorbed into the canons of Thunder Rites within which her name combined with Marici's, her magic assimilated Marici's conjuration, and at the same time, she borrowed Marici's image. Since then, Doumu has not only been the mother of the Dipper, but the main deity of Thunder Rites, and her image has changed from a traditional Daoist female deity into an esoteric Budhisattva. As the characteristics and functions of Doumu were different from Marici, the borrowing image of Doumu adjusted the most prominent feature to her identity and her image thence has specific features of her own. Besides the investigation of image materials and scriptures of Doumu, this paper discusses the meaning of the distinguishing feature of her borrowing image and the main factors prompted this image borrowing.