For utility of economical and practical construction, precast concrete is used due to its advantages such as reliability, durability, and higher quality. The appropriate selection of connection between the precast elements can have a significant influence on both the structural performance and long-term durability of such precast system. In this study, the effects of different connecting techniques on the performance of the precast composite flanged beams were experimentally and numerically investigated. The experimental program included testing up to failure under flexural loading conditions three groups of composite specimens: reference group, mechanical connecting group and chemical connecting group. The numerical assessment was done by using a finite element analysis to get a better insight and analyze the response of tested composite beams that available in the software package ABAQUS. The experimental results showed the advantageous effects of using mechanical connecting technique, as evident from improvement of the ultimate capacity or ductility of the precast composite beams. The results also showed that the predicted structural behavior using finite element analysis in terms of ultimate carrying loads, load-midspan deflection curves and crack patterns of the composite beams was in good agreement with the experimental data.