In the trend toward the development of electronic products that are compact and lightweight, as portable consumer electronic products, such as the cell phone, Bluetooth, GPS, W-LAN, digital camera, wireless phone, and notebook computer, increase in demand, the frequency control components needed for communications related industries receive increased attention. The crystal oscillator is widely used as a frequency selective passive component in communications related industries because of excellent characteristics, such as temperature stability and a low loss. A crystal oscillator consists mainly of a quartz crystal and an IC that controls the oscillation circuits, and is applied to high precision communications products, requiring high frequency accuracy. A crystal oscillator with an output frequency that deviates or is unstable will seriously degrade the quality and functionality of an expensive communications product. This present research investigates the crystal oscillator manufacturing processes, developing risk priority number analysis specifically for critical-to-quality processes and identifying the optimum priority for improvements in the process quality. Using Taguchi experimental design techniques the optimal parameter design is determined for quality characteristics and a mathematic programming method establishes an objective mode for monitoring quality. Lastly, the present research uses a real case to verify the modes proposed in this project, to enhance customer satisfaction, and produce crystal oscillators with a competitive advantage.