it is said oxygen is more soluble in water then why don't it catches fire as oxygen is s0urce of combustion ?????

Three things are essential to start fire. 1) oxygen, 2) a combustible material (fuel) and 3) ignition temperature.
Water is not a combustible material so even if oxygen is present in water it does not catch fire. Water is used to extinguish fire in some cases by lowering down the ignition temperature.