This study is concerned about the optimal design of the base in a vibrating screen. Vibrating screen is widely used for grading and screening materials in the fields such as coal-selecting, mining-selecting, building materials, electrical power and chemical industry, etc. It is composed of base, frame, vibrator, screen, spring, trough, clamp and etc. Especially, base in vibrating screen are stressed by high, mostly shock-type loads. Nevertheless, design of base is dependent on experience, and it will cause reliability reduction and cost increase. The base is composed by the lower plate, the middle plate and the upper plate. This research purpose is to propose and verify a method to achieve higher product quality, lower costs, and far less physical testing. In this study, design parameters used for optimization are the lower plate thickness(7mm, 9mm, 11mm), the middle plate thickness(4mm, 4.5mm, 5mm) and the upper plate thickness(7mm, 9mm, 11mm) in the base. The result showed that base weight reduced to maximum 19.1% when compared with the current vibrating screen.