Saryu Usui (卯水 咲流, Usui Saryū, December 25, 1985) is a Japanese AV actress, actress, model, and talent from Tokyo. She belongs to Diaz Group. Her former stage name was Ayano Moriyama (森山 綾乃, Moriyama Ayano). Her body measurements are 84-59-87 cm (33-23-34 in) (C cup) and her height is 1.67 m. Her hobbies are reading and watching movies, and her special skills are flower arranging and playing musical instruments (trumpet).

In 2006, she won the Clarion Girl Performance Prize under the name Ayano Moriyama. She was affiliated with Oscar Promotion. When she co-starred with Rin Sakuragi in the drama "Jōō" (嬢王) in 2009, she came into contact with the AV industry, which she had always been interested in. On October 16, 2012, she adopted the stage name Saryu Usui and published a gravure photo book in the October 30 issue of Flash. On December 25 of the same year, she appeared nude in the January 25 issue of Weekly Taishu Venus. On February 1, 2013, she made her AV debut with "Souken Bijin" released by MUTEKI. Since June 2013, she has published works with Idea Pocket, and since September 2014 with Attackers. Although for a time she was exclusive to both labels, since the second half of 2015 she has appeared in works for various labels.