Natural surface has kinds of sophisticated micro structures which formed various superior functions such as drag reduction through biological evolution. However, such function performs to maximum just at its living environment. In order to adjust the optimal function region of natural surface, one novel approach, bio-scaling forming process, is proposed to by taking advantage of solvent-swelling effect of Polydimethylsiloxane. To realize the accurate replication of bio-scaled shark skin, swelling ratio and swelling rate in gaseous n-Hexane are investigated. The accuracy of bio-scaling processing approach is verified by comparison between micro-structure of original and amplified shark skin, which shows that the swelling ratio can reach even to 34%, and the bio-scaling processing accuracy is higher than 95%. In addition, both the water contact angle and the optimal velocity range of drag reduction will change with the amplification.