過去關於產品組合決策的研究，主要分為兩大類，一類為針對不同的成本制度進行比較，另一類則是採用電腦模擬或數學模型推導出最適產品組合決策。然而，產品組合決策建構過程的思考邏輯比最終架構更具關鍵性，因為思考及評估過程中的完整性決定最終架構的適用性。又因為投標市場中，投標廠商可能有多種不同成本的產品同時符合投標規格需求，且每一個標案都對投標公司的損益有重大影響性，因此在電信投標市場中適宜的訂價及產品組合決策更是重要。故本研究選擇以一家通訊設備廠商為個案公司，深入探討該公司如何在電信投標市場中藉由導入作業基礎成本制度（ABC）與改革產品組合決策，來提昇公司的獲利。個案公司改革後的產品組合決策像以市場導向策略規劃方式為出發點，亦即先考量願景，再接續考量內外部環境及公司定位後，最後推導出公司的產品組合策略。再根據前述策略推衍出公司的產品組合決策考量因素。研究結果顯示相較於改革前，改革後的累積毛利約為改革前的3.13倍，而累積淨利則為27倍；故本研究結果有助於補充以往產品組合決策相關研究之缺口，並可供產業界參考之用。 The literature on product-mix decisions can be categorized into two groups. The studies in the first category compare different cost systems, whereas studies in the second category determine the best product-mix decision using computer simulations or mathematical models. However, product-mix decisions are important not only for the final structure of the product-mix but also for the decision-making process. The comprehensiveness of the decision-making process has a pivotal effect on the appropriateness of the outcome. In particular, in the telecommunications bidding market, pricing and product-mix decisions are indispensable. This is because of certain special features of the telecommunications bidding market. Producers may have many products that conform to the specifications of buyers, but these would have different prices. Each bidding project can have a huge impact on a company's profit or loss. This study considers a communications equipment company operating in the telecommunications bidding market and examines how this company can increase its profits by using activity-based costing to improve its product-mix decision.After making the improvement, the product-mix decision of the company is based on a market-oriented strategic planning method in which the vision is first clarified. Then, it is followed by an analysis of the internal and external environments. Next, the company's positioning choice is made; finally, the company's product-mix strategy is derived. According to the company's product-mix strategy, the main factors that influenced the product-mix decision are deduced. The results reveal that the accumulated gross profit after the improvement was 3.13 times greater than that before the improvement, and the accumulated net profit after the improvement was 27 times greater than that before the improvement. The results of this study complement the existing literature and provide implications for companies in the bidding market.