He is famous as a singer.

be famous as 后一般跟 人，表“做为......人而闻名”

be famous for 后一般跟事物 ,表“因/由于......而闻名”

be famous to 后一般跟 人，表“对......是熟悉的”，“为......所熟知的”

以上as, for, to都是介词。

例如:

1. Lu Xun is famous as a great writer.

Lu Xun is famous for his great novels.

祝你学习进步，更上一层楼！ (*^__^*)

不明白的再问哟，请及时采纳，多谢！