來華傳敎嘅僧人爲學習漢語嘅語音，他們自然會採用喺印度通行嘅一種練音方式，呢種練音方式所使用的敎本喺梵語裏稱作悉曇（siddham），悉曇就是將梵文的元音一個個輪流與輔音相拼而製成的音節表。於是就有人對韻書加以分析後仿照悉曇的模式繪製咗漢語嘅音節表，呢個就係韻圖。
In order to learn Chinese pronunciation, monks who came to China naturally adopted a method of pronunciation that was common in India, and the text used in this method of pronunciation was called siddham in Sanskrit, which is a syllabary made by alternating Sanskrit vowels with consonants. Therefore, some people analyzed the rhyme book and drew a Chinese syllabic list according to Xi Tan's model, which is the rhyme map.