Abstract: Secret History of the Yuan Dynasty, which has been handed down to the present, is a version of phonetic Chinese characters, which was copied by many people, and there are many paraphrased and incorrect characters. Ulan's Secret History of the Yuan Dynasty (Collated Edition) is widely used in various editions, keeping its original layout, and comprehensively collating the transliteration text, side translation and general translation. It is the mainstream edition for studying the Secret History at present, and can best see the collating foundation of Mrs. Ulan's Secret History. Limited by objective conditions, there are still some problems in Ulan's collating, such as deviation, error and improper proofreading. Combining with several existing collations, this paper not only makes use of Mongolian materials, refers to transliteration conventions, but also takes into account the factors such as pronunciation and application of Chinese characters, so as to correct the omissions in Secret History of the Yuan Dynasty (collated version) and present the basis, in order to be beneficial to the collating work of ethnic ancient books.