In order to systematically study the damage of drilling fluid pollution to Marine low permeability gas reservoir， the laboratory test and evaluation method were adopted to carry out the experimental analysis of drilling fluid pollution by selecting the natural core of the target reservoir under the precise simulation of formation conditions， and the influence of drilling fluid pollution on productivity was quantified. The research shows that the damage rate of permeability decreases with the increase of original permeability under the same displacement differential pressure after drilling contamination， and almost all permeability is lost for cores reaching the tight grade. Increasing the differential pressure further aggravates the permeability damage of the contaminated core. The drilling fluid damage is mainly caused by the complex multi-grade particle size plugging， and the permeability damage is divided by the displacement differential pressure of 0.6MPa. The reservoir damage is more serious when the displacement differential pressure is increased within 0.6MPa， and the damage in the later period is generally small. With the increase of displacement differential pressure， the spacing of permeability damage rate curves of cores with different original permeability becomes smaller and smaller， and the curve shape gradually transitions from large radian of higher permeability to "straight line" shape of lower permeability. The impact of drilling fluid pollution on the productivity of the target reservoir is more than 93%. Therefore， it is suggested that the Marine low permeability reservoir with drilling fluid pollution should not be easily opened for production before plugging is removed. The research results provide important technical support for the development of Marine low permeability reservoir.