The purpose of the study is to analyze the problem of offer pricing and share issuing in the issuer with a dynamic model. The result shows: First, the correlation between discount and the prosperity of the market is not a linear function. Thus, ¡¥the IPO¡¦s timing¡¦ should be the key issue of issuing firm, which can reasonably explain the fluctuations in underpricing over time. Second, we also discover that the relationship between the ownership structure and the prosperity of the market is not a liner function as what Bolton and Thadden (1998) have claimed. Third, the firm with low quality prefers to release issuing shares in IPO when the market is booming. Fourth, the less the IPO discount in traditional industry, the more the share releasing. Finally, the more the phenomena of subscription, the more the investors subscribe blindly and generate an effect of the cascade. One of the contributions in this model comprises the views between the prosperity of the market and IPO discount in the literature to integrate a profound viewpoint by dividing the IPO discount into the offer pricing error and the market pricing error. Another finding is that the offer pricing error will decrease subject to the prosperity of the market. This is consistent with the viewpoint of Chemmanur (1993) that when the market is booming, the issuers can decrease the cost of adverse choice. As for the non-linear relation between the market pricing error and the prosperity of the market is coordinate with what Ma(1999) has claimed that IPO discount is influenced by the offer pricing and the market pricing. Besides, the non-linear relationship between ownership structure and the prosperity of market can reasonably account for the real situation. Besides, the benefit of controlling authority is better than the value of the cash flow of the released shares owing to the depression of the market, even the market is turning booming. Therefore, the issuers will minimize releasing share. However, the issuers will increasing released shares up to the market is keeping booming and the value of the cash flow of the released shares is better than the benefit of controlling authority. An auction model is established to analyze the choice of firms between fixed-price offerings and auctions. Chemmanur and Liu(2003) stated that obtaining the auction information is more advanced; however, the cost is high so that it can not catch enough investors to produce information which does not favor the discovery of the secondary market price. On the contrary, we proclaim that the information transmitting effect produced by auction will be helpful to the discovery of the secondary market price. Thus, a profitable company but suffers from high levels of information asymmetry prior to the IPO might expect the secondly market price to reflect its real value by auction. Moreover, the choice of underwriting mechanisms lies in the prosperity of the market, the reputation of the company and the degree of the releasing shares. The result of the empirical study is consistant with the expectation of our model.