As the boost of society, 3D modeling technology is also extensively utilized in various fields, and it also faces more new users and new opportunities. Amateur users' demand for 3D models is gradually increasing, but conventional 3D modeling software requires high basic knowledge, strong professionalism, and complicated operations, making it difficult for users to master. In response to this problem, the research combines the characteristics of the mobile terminal and proposes three modeling algorithms in view of contour recognition. Meanwhile, the interactive interface is divided into editing mode and viewing mode, and a mobile terminal sketch-style 3D modeling technology based on interactive design is designed. The experiment illustrates that the modeling time of the sketch-fitting algorithm is 3.04 min and 3.16 min, while the modeling time without the sketch-fitting algorithm is 4.48 min and 5.06 min. When the expansion coefficient is 25 and 100, it is found that the smaller the expansion coefficient is, the flatter the model expansion effect is, and the larger the expansion coefficient is, the more round the model expansion effect is. In the overall modeling test, the average score of users on the ease of use of the software is 4.357, and the sample standard deviation is 0.515. To sum up, the 3D modeling technology proposed by the research is more suitable for non-professional users. Users can easily master and understand the 3D modeling method, and design their own personalized models more quickly.