In order to reach the economic scale, reduce unit cost and to enhance the international competitiveness, China Steel Cooperation constructed a subsidiary - Dragon Steel Cooperation, a 5-million-ton integrated steel plant nearby Taichung Harbor. Starting from iron-smelting, steel-making till steel-rolling, each step follows one another. If any of the steps occurs a problem, the whole production will be affected. The quality of the new construction is related to the life cycle of the equipments, the stability of the operation and the quality of the products. Further more, if the new construction is imperfect, there might be plenty of accidents, such as public safety, environment issues, protest from the inhabitants, etc. The influences could be huge. The main quality influences of the new construction work are low bids from the contractors, shoddy work and use inferior material during the construction, lack of control, welding problems, etc. According to the above main factors, we listed 20 secondary factors, e.g. bad financial situation, vicious competition, budget shortfalls, etc., and use analytical hierarchy process to find the relationship between them. In this thesis, there are in total 32 people have been interviewed, 8 of them are first-line supervisors (the up, middle and downstream of the steel plant, from steel-smelting plant, steel-rolling plant, public facility department to civil department.) Meanwhile, 10 senior executives are also interviewed; relevant literatures are used as related inference. Via this analysis, the most important factor of influencing the welding quality of new construction work is ¡§welding problem¡¨ with 0.297 rating point. Analyzing the third layer factors of low bids rating, the highest point is ¡§vicious competition¡¨ with 0.354. In shoddy work and use inferior material factor, ¡§changing subcontractor frequently¡¨ is the highest with 0.491 rating point. In false inspection, the ¡§progressing pressure¡¨ is the highest with 0.378 rating point. In welding problem, the ¡§construct without drawing¡¨ is the highest point with 0.371. In other factors, ¡§defected raw material¡¨ is the highest with 0.275 rating point. If the above problem solved, the welding quality in new construction work will improve tremendously. Keywords: non-destructive testing, quality of construction, new construction work, turnkey contractors, defect.