Rht4 is classified as a GA-responsive and recessive dwarf gene in bread wheat (Triticum aestivum L.). The agronomic traits such as plant height, length of internodes, yield and yield components of Rht4 in bread wheat had been evaluated, but the responsiveness of Rht4 to exogenous GA3 on important morphological and agronomic traits were unclear. To further understand the role of GA on the important agronomic traits of Rht4 in bread wheat, the F4:5 and F5:6 dwarf and tall lines derived from a cross between Jinmai 47 and Burt ert937 (Rht4 donor) were treated with exogenous GA3 in this study. After exogenous GA3 application, the plant height of F4:5 and F5:6 dwarfing lines were significantly increased by 18.12% and 16.96% than the control ones, compared with that of tall lines by 9.67% and 6.07%. The grain number spike-1, 1000-kernel weight (TKW) and the seed thickness of the dwarf lines notably increased with exogenous GA3 application, but no remarkable differences were observed on the spikelet number spike-1, the seed length and width comparing with the control ones. What’s more, the crude protein, wet gluten, sedimentation value, stability time, development time of the dwarf lines with exogenous GA3 application were significantly increased. To sum up, the results showed that Rht4 was a GA-sensitive dwarf gene, the application of GA3 could compensate some of its negative influences, which may provide further reference for its application in wheat breeding program and promote the study in characterization of its regulatory mechanisms.