The construction system of load bearing wall is a widespread system where it is an economic and easy to implement method. The most important construction materials used in building walls bearing system are (stone, clay unit, calcium silicates units and concrete masonry units), in this research it has been studied the behavior and strength of limestone. Limestone found in vast areas of the Egyptian deserts such as the Giza, Saqqara, Tourra, Matrouh and Minya. Therefore, an experimental program consisting of three stages was developed. The first stage includes testing units of limestone to determine their physical and chemical properties. In the second stage, building masonry prisms constructed from limestone used two types of mortar no.1 and 4 mixed according to the Egyptian code for designing and executing masonry works, where the tests conducted (compressive strength, shear strength, tensile strength, in plane and out of plan). As for the third stage, it includes testing six walls under the influence of axial load, as these walls are divided into two groups: the first group was built by using mortar no. 1, while the second group was built by using mortar no. 4; each group is divided into three types of walls. The first type was a solid wall; the second was a wall with a window opening, while the third was a wall with a door opening. The results showed that the compressive strength of walls that were built by using mortar no. 1 is better than those that were built by using mortar no. 4