Lap splice in RC beams are the most commonly used to connect steel reinforcement in different elements in structures and usually the least expensive one. The integrity of the lapped splice depends on the development of adequate bond along the surface of the bars on the ability of the concrete around the two bars to transfer shear without disintegration or excessive deformation. The behavior of light weight reinforced concrete (LWRC) beams was tested experimentally and theoretically evaluated in this study.. Six LWRC beams consist of simple beam 3000mm between two support with cantilever 500mm and with cross section (400*150)mm were tested in experimental test using lap splice in positive and negative bending with the loading system designed specially to study the behavior of LWRC with tension lap splices. The test results including deflection behavior, crack pattern , failure mode, longitudinal steel strain and bond stress are presented and discussed. Seven light-weight reinforced concrete beams (LWRC) were tested in theoretical test using finite element analysis (ANSYS 14.0). Results show that good acceptance by experimental and theoretically study.