I am packing some clothings, computer, and planning to ship via Postal Office to Switzerland for personal use.

Will there any tax from Swiss Custom? I hope it will not be too much troubles.. shipping is not cheap from USA to Switzerland.

You might Google 'excess baggage shipping from usa' and talk to one of those specialized firms about Swiss Customs clearance. Their use of a customs broker is likely to get you a better deal than the postal system, and they will give you guidance on how to fill out the customs forms.

Personal effects are not subject to tax and duty. The rules are here.
http://www.ezv.admin.ch/zollinfo_pri...x.html?lang=en

While this is true you need to state that the goods are personal effects associated with a move to the shipping agent responsible for shipping and you need to personally come and pick the things up from the collection point at the border which is usually at an airport or tax free warehouse. This can be a royal pain so make sure you know where the delivery point is.