In order to determine the product platform in product family design, the concept of Function Similarity was discussed, which was aimed at the function similarity of different products, and a new method to construct platform of function similar products was put forward based on bottom-up approach.

Chen argues that"functional equivalence"is an idealistic standard,and that when a translator finds it hard to reach the"equivalence",he has to seek"functional similarity"as the realistic standard.

In practice as the generally accepted translated terms cited in this paper show,what a translator always looks for is only"partial functional equivalence"or"functional similarity",when real "funct.