The "Usability" is a term which shows to what extent can user handle products with easy and convenience is regarded as a key factor evaluating products.
Nowdays, with the rapid development of current technologies, the system has been large-sized and multifunctionalized. As the result, the complexity of products has been increased and the usability come to the core.
As designing products, the main factor, when it comes to the usability, should be able to evaluate differences among users who characterized by capacities of use and characteristics of use. As a matter of fact, up to now, studies dealing with so-called usability have been fallen short in classification of users.
So this study classifies the behavior of use by three variable factors; the first is the time taken by accurate operating with accurate rule, the second is the number of accurate rule which user hsa, the third is recovering time after commiting error with unaccurate rule, based on these factors, establishs the characteristics of use by clustering user.
In conclusion this study propose design guideline based on these characteristics of user groups.