i found this.
source :
http://halalisbetter.com/halalharamdiscussion.html
I work in a retail business and after I ordered some shoes I figured out the it is made from the PIG leather, so is that halal or haram to trade in the pig leather, and if it haram, what should I do in my stock, throw it away or just sell it and don't order it any more, specially that I can't refund it from the supplier (question from Zulkifli - Malaysia)
1) Allah mention in Quran surah An-Nahl 115 about forbidden flesh as follows: "He has only forbidden you dead meat, and blood, and the flesh of swine, and any (food) over which the name of other than Allah has been invoked." It is very obvious that flesh of dead animals and flesh of swine are in the same level, they are forbidden.
2) Hadith shahih Buchori (5531). Narrated 'Abdullah bin 'Abbas: Once Allah's Messenger passed by a dead sheep and said (to the people), "Why don't you use its hide?" They said, "But it is dead," He said, "Only eating it, is prohibited ."
3) Hadith shahih Buchori (5532). Narrated Ibn 'Abbas: The Prophet passed by a dead goat and said, "There is no harm if its owners benefit from its skin."
4) There is no Hadith mentions pig skin, however, from those three references above, we can pull qiyas (extrapolation) that tanned skin of any animals, including tanned pig skins, are not prohibited to wear. However, since it is qiyas, you need to aware that some ulama' may have different opinion with other ulama'. Allah knows best.