In cold regions

ice accretion will seriously degrade the insulation performance of high-speed train roof insulators

causing partial discharge and flashover accidents and resulting in suspension of train

and enormous economic loss.However

the research focusing on this issue is rarely available in the literature. In this paper

computational fluid dynamics（CFD） based numerical simulation research is performed to investigate the ice accretion on FQJG2-30/16-400 silicone rubber composite roof insulators at different environmental conditions. The results show that

when the train runs at high speed

the ice mainly accretes on the roof insulators’ shed edges and rods in windward side

and the largest ice thickness appears in the center of the windward side. The results also show that the ice mass on insulator increases with the augment of environmental parameters including temperature（θ）

wind velocity（v）

liquid water content（LWC）

and droplets median volume diameter（MVD）. Based on anti-icing structure optimization research

it is suggested that anti-icing configuration for high-speed train roof insulators are as follows: the recommended values for lower tilt angle and sheds ratio are 0° and 1

respectively; when the mechanical strength meets the requirements

the upper tilt angle and rod diameter should be smaller to the utmost; the sheds spacing should be smaller to the utmost when creepage distance meets the requirements.