As internet varies with time, action websites goes better integrated accordingly. Earlier in Taiwan, the operation way of online auction was between traditional auctions and flea markets, mainly in order to undersell private stock. Gradually, this business was worked as sideline, starting with sales of low-priced stuff. Nowadays, online auction was considered as an access to expand business scope, which appeals to huge amount of participants. Thus, a refined operation pattern is established. The research on sellers of online auction is based on Grounded Theory. By analyzing the data collected from the four interviewers, through theoretical sampling process, this research generalizes twenty-two open coding and five axial coding. The result shows the key factors of successful on-line auction are business strategy, external environment, cost, customer management and target of the further.