An LED lamp tube with improved sealing and cooling performance includes a plastic tube shell, an LED lamp strip, a metal casing and two end caps. The plastic tube shell is elongate and includes a light condensing structure and a light reflection structure integrally formed by extrusion and an installation chamber formed between the light condensing structure and the light reflection structure. The LED lamp strip is held in the installation chamber and at one side of the light reflection structure. The metal casing is coupled on the outer side of the light reflection structure. Each of the end caps is coupled on each of two ends of the plastic tube shell, thus can achieve IP67 waterproof and dustproof level, and also can resolve cooling problem of the lamp tube.