"用拟声唱法唱" can be translated into English as "sing using onomatopoeic vocal techniques" or more colloquially, "sing with onomatopoeic singing style".
Here, "onomatopoeic" refers to words that imitate natural sounds (like "buzz," "hiss," or in a musical context, vocal effects that mimic sounds), and "vocal techniques" or "singing style" conveys the method or approach of singing.
If you want a more direct and less technical translation, you could also say "sing in an onomatopoeic way".