Abstract: Silicone rubber composite insulators running in coastal or mountainous areas are always in the harsh environment of high humidity and large temperature difference, and the problem of creeping discharge induced by condensation has brought great challenges to the operational reliability of composite insulators. In order to study the mechanism of condensation generation and development on the surface of silicone rubber, we firstly constructed a full-cycle numerical simulation model of wet air droplet condensation considering the role of non-condensable gases on the basis of the existing droplet condensation model, and adopted the neighboring droplet logic searching algorithm to improve the operation efficiency of the model. The validity of the model was then verified by a silicone rubber wet air condensation test. Finally, we discussed the influence law of environmental temperature and humidity, physical and chemical properties of condensation substrate on the development of condensation. Finally, we explored the law of influence of factors such as ambient temperature and humidity, and the physical and chemical properties of the condensed substrate on the development of condensation. The following conclusions can be drawn: The pre-condensation droplets grow mainly by direct condensation, while the later period is dominated by agglomeration growth, and the contribution of coalescence growth to the maximum droplet radius at the later stage of condensation is more than 70%; The condensation growth rate is positively correlated with relative humidity and temperature difference, and negatively correlated with material thickness and static contact angle. This study helps to reveal the mechanism of wet air droplet condensation, which can provide the corresponding theoretical basis and technical support for the improvement of anti-condensation performance of insulating materials and the prevention of condensation in electrical equipment.