This article integrates intelligent 3D simulation technology with an online customized clothing system to increase the impact of customized clothing design. The user uses a 3D scanner to scan his own body and acquire 3D body data, which include information of the head, chest, upper limbs, lower limbs, hands, and feet. Furthermore, this work enhances intelligent tracking and recognition technology, enhances the impact of human body parameter collection, and combines the enhanced algorithm to create a personalised clothing design system based on intelligent 3D simulation technology. Through experimental research, it can be seen that the customized clothing design system based on intelligent 3D simulation technology proposed in this paper has good effects and can effectively improve the service quality of online customized clothing.