已解决.
List<IMyTerminalBlock> lights = new List<IMyTerminalBlock>();
void Main()
{
lights.Clear();
GridTerminalSystem.GetBlocksOfType<IMyReflectorLight>(lights);
Color lightColor = lights[i].GetValue<Color>("Color");
lightColor.R = (byte)255;
lightColor.G = (byte)0;
lightColor.B = (byte)128;
lights[i].SetValue("Color", lightColor);
}
查询了API后发现Color这个类