In the band's earlier days, their musical style tended towards light, cheerful and/or refreshing songs. However, the sound has changed in recent times to take on a darker and more mysterious tone. Takarano Arika, lead singer/lyricist, has termed this change as a transition from White Alice (白アリ, Shiro Ari) to Black Alice (黒アリ, Kuro Ari). Though there has been a general shift towards performing songs in the "Black Alice" phase, Ali Project has occasionally sung in the White Alice style as well.
They made their indie debut in the charts in 1988 as Ari (Ant) Project (蟻プロジェクト, Ari Purojekuto) with their album Fantastic Garden (幻想庭園, Gensō Teien). The album was later included in Tatsumi Takayuki's book Philosophy of Progressive Rock (プログレッシヴ・ロックの哲学?), which led to the band being classified under the progressive rock genre.
Four years later in 1992 they changed their name and made their major debut with their single Fall in love, maiden (恋せよ乙女, Koi-seyo otome).
Most of their records are released by Toshiba-EMI, Victor Entertainment and Tokuma Japan. The band is notable in the anime community for having their songs featured in several anime opening and ending sequences, most notably in the series Noir, Rozen Maiden, Linebarrels of Iron, and Code Geass. Additionally, Katakura Mikiya has also provided the soundtrack to several anime series, such as Kaibutsu Oujo and Avenger.