資訊系統的運用已是現代企業經營不可或缺的一環，然而，應用系統的開發通常不是一般企業的核心能力，故委外開發是大多數企業在建置資訊系統時最常用的選項。企業在進行委外開發之前，可能因未將資訊系統的建置與企業經營策略校準、或因缺乏理性的選商流程與評估標準、或因在議約時純粹以殺低價格為主要考量，而錯選到一個不合格的承包商。如果再加上使用者的需求說不清楚，開發人員的質與量不符所需，雙方對各自的權責沒有共識，專案管理能力不足等，則這種委外開發必然會問題不斷，最終以失敗收場。 為提高委外開發的成功率，本論文首先將「應用系統委外開發」重新定義為「在合約關係下，承包商依據客戶的需求，為其規劃、開發、導入、維護所需的資訊應用系統。在系統建置過程中，客戶的主要人員，必須積極地參與承包商的開發活動，包括提供需求說明，驗證與確認（verify & validate；V&V）階段性產出的正確性及可用性等，以確保承包商可以如期、如質、如需求地在預算內完成所委託的交付項目及服務。」以導正觀念。然後再透過「應用系統開發委外專案之業務及開發流程」的介紹，分別從客戶及承包商的角度，提出正確的業務及開發流程，期以拉近雙方的共識，並印證應用系統委外開發的成功，必須靠雙方的共同努力。 當承包商了解客戶在委外決策時所面臨的問題及顧慮後，即可透過4C策略行銷的分析，設計出能夠解除客戶疑慮的方案，建立共識，降低雙方的交易成本及風險，以確保委外合作有個好的開始。本論文從承包商的角度以4C架構進行行銷策略分析，最終得出46個策略，並依照專案的生命周期歸類，以協助承包商隨著專案進展也可以很方便地檢視各種策略組合，故即使是在多專案併行時，依然能有效掌握各種策略的執行，提高應用系統委外開發專案的成功率。 / The use of information systems is an absolutely necessarily in a modern business operations, however, application development usually is not a core competency of the most of enterprises, thus making development outsourcing becomes the most common option for the most of enterprises while they are establishing information systems. But, before the enterprises move forward development outsourcing, they may not align the establishment of information system with the strategies of business operations, or lack of rational processes and evaluation criteria in vendor selection, or only solely consider the lowest-priced while in contract negotiation, thus wrongly selected an unqualified contractor. In addition, if users cannot express requirements clearly, the developers’ quality and quantity do not match the requirement, no consensus on respective responsibilities of the parties, and project management skills shortage, etc., then this kind of development outsourcing shall have problems at every moment, and they will definitely end in failure. To increase the success rate of development outsourcing, this paper firstly redefines “Application Development Outsourcing” (ADO) as "Under a contractual relationship, the contractor shall, pursuant to customer’s requirements, performing the tasks of planning, developing, implementing, and maintaining of the required application system. In the course of the system development, the customer’s key personnels must actively participate in the contractor's development activities, including provide requirement specification, verify and validate the correctness and usability of the output by phases, etc., to ensure that the contractor will be able to deliver the deliverables and service on time, as required quality, as required functionalities, and within budget." The purpose of this redefinition is going to correct perceive of ADO. And then thru the content of “ADO project business and development process”, describes, from the point of view of the customer and the contractor, the “shall-be” business and development process, for closing the gap of the parties, to reached a consensus, and proving the success of ADO, must rely on the concerted efforts of both sides. When the contractor realizes custome’s problems and concerns while deal with ADO decision, then can based on 4C strategic marketing analysis theory, design the solution that can reolving customer’s misgivings scenario, to build consensus, to reduce the transaction costs of both sides and risks, to ensure that outsourcing cooperation there is a good start. This paper, from the point of view of the contractor, based on 4C marketing strategic analysis theory, resulting 46 strategies, and classify them in accordance with the project life cycle, to assist the contractor can also be easily to review the various strategic groups, as alogn with the project progress, thus making even in a multiple project circumstance, still be able to keep track of the implementation of various policies, to improving the success rate ADO projects.