As a new energy-saving and environmental protection building material, dry-mixed mortar has been promoting actively in China. The key techniques of control system for dry-mixed mortar production line were introduced in this paper, which was mainly based on PLC and smart weighing instrumentation. Firstly, the technology process and control demands were presented. Secondly, control system configuration, control strategy were proposed in detail. Finally, the key intelligent adjust algorithms were described as well. The practical operation verifies that the control system is highly reliable and stable, and it greatly enhances the level of automation and weighing accuracy of the raw material and meets the equipments requirements of energy-saving and green running.