Experiments were conducted on 5 simply-supported composite steel-concrete beams (SCB) with compact steel sections to investigate their deflection behaviors. The influences of degree of shear connection and stud arrangement are discussed. The load-deflection relationships and the interface slip distribution along the span of the beam are analyzed. Based on the experimental research and theoretical analyses, the formulae are derived for the rigidity of the composite steel-concrete beams with partial shear connection. The predicted of deflection values are in good agreement with the experimental results.