This paper focused on the problem of imprecise categorization of software behavior data, using relative data mining techniques to find determined categorization of software trustworthiness which represents the consistency of software behavior and its claim. In detail, addressing to the measurement method of software trustworthiness mentioned above, this paper propose a new measurement framework for software trustworthiness based on imprecise categorization. We firstly define the formal representation of software trustworthiness according to its definition about imprecise categorization. Secondly, we introduce relative measurement framework about imprecise categorization and its application approaches in measurement for software trustworthiness. Finally, we make the conclusion of this paper and discuss some research area in software trustworthiness in future.