A method of conducting transactions over the Internet, comprising the steps: opening an online market; applying membership, wherein a member is classified into classes A, B or C; class A member is a professional institution/person who provides security services for a market transaction order; class B member is a seller/provider who participates in network goods/service transactions; and class C member is a purchaser who participates in the network goods/service transactions; establishing a market website; equipping with a website server; drafting market rules; wherein class A member verifies authenticity of general and performance information, which are inputted into market website server by a market administrative institution, declared by class B member; the members learn about financial conditions from one another via the Internet by using a network terminal unit, and negotiate online transactions and sign a contract; and the seller/provider provides goods/service, whereas the buyer fulfill online payment.