Taiwan carries out the new underwriting rules since 2005, it is very important to the reformation of financial system, and its purpose is mainly for responding to the reformation of underwriting rules so as to promote the quality of listed companies. At present, the underwriting method of Taiwan¡¦s major Initial Public Offerings (IPO) stock uses the mix and collocation of two systems, public subscription by lot drawing and book building, as the underwriting method, the previous studies emphasized that the underwriter had higher right to decide the amount of placing, which can increase the responsibility and sensibility for the underwriting price, and then the result of promoting placing efficiency can be reached. This study compares the markets in Mainland China, Hong Kong, and Taiwan that have carried out book building system. This study mainly finds out, because the underwriters in Taiwan can provide higher stock weight of the placing of book building and the underwriters have higher right to decide the amount of placing, thus, it is more possible that when placing IPO stock, the company would regard its customers as the core, and this act is entirely different with the conception of the initial reformation, and unfavorable influence would be produced to the issue company or individual investor at the same time. This study sums up the previous literatures and questionnaire statistical analyses, and then proposes the influence that degree of rigor of laws and regulations, anticipated result of placing, institutional function of book building and decisive factors of placing have towards the actual results of placing of underwriters. The questionnaires are distributed to the personnel who actually are responsible for the IPO placing strategy of underwriters that have hosted actual placing results in Taiwan, Hong Kong, and Mainland China. After the comparison using single factor variance, one can find that the underwriters from Mainland China significantly think that the laws and regulations are stricter, and IPO stock has more good prospects of gain. However, the underwriters from Taiwan significantly think that the decisive factors of placing are stronger. When placing IPO stock, the underwriters from Mainland China prefer placing according to the system, while the underwriters from Taiwan prefer placing according to relationship. This study uses regression analysis to discuss the factors that influence the underwriters to carry out placing according to system or relationship. This study finds out if the degree of rigor for the two factors in laws and regulations, objective & fair and book building standard, is higher, then the underwriters will tend to carry out placing according to system more. And also, the system-oriented and price-oriented factors in decisive factors of placing also promote the underwriters carry out placing according to system. On the other hand, if the degree of rigor for the objective & fair factor in laws and regulations is higher, then the underwriters tend not to carry out placing according to relationship. When the factors such as considering underwriter¡¦s benefits, anticipated profit, and relationship-oriented are higher, then the underwriters tend to carry out placing according to relationship. In view of the above, this study has proposed many suggestions to improve the problems that might happen when underwriters in Taiwan placing IPO stock at present, including report beforehand, exposing the principles, ratio of book building placing, classifying the investors and placing in proportion, regulations of holding term, strengthening the supervision on notary public during the placing process, and canceling the use of person as the basic unit when purchasing but the use of purchasing capital¡¦s scale as the drawing unit. This study also hopes that the relevant departments in governments and underwriters could consult this study thesis and take this study as the reference for the follow-up reformation direction of IPO system.