In　order　to　develop　reasonable　modular　product　architecture　with　physically　detachable　modules,　a　new　systematic　method　for　product　modularization　is　proposed　based　on　axiomatic　design　(AD).　In　the　proposed　method,　the　product　is　decomposed　hierarchically　in　its　functional,　physical　and　process　domains　according　to　AD.　After　the　transformation　from　design　matrices　to　design　structure　matrices,　the　correlation　design　structure　matrices　of　design　parameters　about　function,　structure　and　manufacturing　process　are　constructed.　Finally,　a　genetic　algorithm　combined　with　the　minimal　description　length　is　introduced　to　solve　the　modularization　optimization　problem.　To　illustrate　and　validate　the　effectiveness　of　the　proposed　methodology,　an　indoor　air　conditioner　unit　is　presented　as　a　demonstrative　example.　©　2012　IEEE.