This work aims at studying the degradable effect of natural and artificial ageing on tri-layer polyethylene films used as greenhouse cover in the North Africa environment. The film was supplied by Agrofilm and made of low density polyethylene (LDPE), containing additives (e.g., color and infrared IR and ultraviolet UV stabilizers). This film was used to build a real greenhouse located in the North of Algeria. Impact of ageing was monitored by observing the changes in mechanical (strength and ductility) properties. The study has been carried out over a period of eightmonths of natural and artificial ageing. The films have been artificially aged at 40ยฐC, 40ยฐC + UVA, 50ยฐC and at 50ยฐC + UVA. The findings show that the environmental factors have degradable effects on the durability and all properties of the polyethylene film. The study revealed also that the degradation parameters measured are directly related to criteria for evaluating the effectiveness of agricultural greenhouse. The simultaneous effect of temperature and UVA radiation induced the most significant degradation on the film surface and consequently a reduction in the lifetime of the material.