Abstract: Miniature transformers has complex working conditions, the parameters of which are multi-valued, nonlinear, environmentally dependent and difficult to detect. Therefore, miniature transformers must be designed as the case may be, and the contribution rate of design to product cost performance is as high as 70%. Most transformers are based on feasible design. Optimization design may compromise multi-objective under constraints, whereas, the multi-variable nonlinear equations for the optimization design have neither analytical solutions nor useful numerical solutions easy to find. Consequently, we put forward a visualization algorithm for optimization design. The chromatogram in 3D space corresponds to the value range, and the spatial distribution of multi-objective constraint intersection set is used for interactive optimization. In order to reflect the market price of wire and core, the window rectangle coefficient is proposed as the decision variable. In order to reduce the loss cost, the leakage inductance of non-concentric windings is used to replace the inductor in LC filter. The design data and experimental results are given, and the effect of optimization design is verified by comparing with the data of similar transformers. Combined with the mathematical model, the program code and the generated image are given accordingly, so that the 4D visualization algorithm can be used as a reference for other optimization designs.