［Objective］To address the technical challenges of waterborne iridescent coatings in the rail transit field，including unstable iridescent effects，poor compatibility with supporting coatings， and limited application performance.［Methods］A systematic study on the preparation technology andapplication properties of waterborne iridescent coatings was carried out. The research focused on exploring the influence of key components，such as the main resin system，parameters of iridescent powders，and orientation aids，on the coating properties.［Results］Through comparative analysis of the film-forming characteristics of different resin systems，a ternary composite system consisting of waterborne acrylic resin emulsion，low-hydroxyl and high-hydroxyl waterborne hydroxyl acrylic resins at a 1∶1∶1 mass ratio（solid basis）was determined. A composite iridescent powder with multi-levelparticle size distribution and surface passivation treatment was optimized，and a synergistic orientationtechnology using organically modified montmorillonite clay and ethylene-vinyl acetate copolymer wax（EVA）was adopted. The optimized coating system exhibited excellent comprehensive properties anddemonstrated superior compatibility with various polyurethane primer and glossy varnish under complexworking conditions.［Conclusion］An environmentally friendly iridescent coating system suitable forthe rail transit field was successfully developed，which integrated environmental friendliness，high decorative performance，and excellent comprehensive properties，providing an effective technical solution to the environmental protection and functional application challenges of coatings in this field.