With the vigorous development of China’s chemical industry, the scale of investment in construction projects of chemical enterprises has been expanding. Although China has accumulated rich experience in construction project cost, it has not yet established a relatively complete construction cost management technology system of chemical plant. Based on the dynamic management technology, this paper studies the construction cost of chemical plants. Then, through analysis of the factors affecting the construction cost of chemical plants, it establishes the technical system of construction cost management for chemical plants. The analysis results show that this management technology system can realize the control target in the construction cost of the chemical plant. The established dynamic evaluation model of cost can greatly improve the actual project cost control level. It has wide practicality and is worthy of promotion.