Abstract: The technique of FRP (fibre reinforced polymer) fast strengthening steel members is presented in concept and operation. The effectiveness of the technique is proven through the preliminary experiments of three specimens. Then, another 14 specimens have been tested under axial compressive loading, through which the compressive behaviour and strengthening effects are investigated with different configuration parameters, including two slenderness ratios, two confinement configurations (pultruded FRP profile and hand lay-up fibber sheets), two filled materials (mortar and bamboo splits) and the end connections (confined end-plate connection and single sideband pinned end conditions). The strengthening effects are analyzed by the comparison of both theoretical and test results, which shows that the overall buckling failure of steel members can be prevented by FRP strengthening, and the ultimate loading capacity and deformation capacity of steel members are enhanced obviously. The highest loading capacity of a strengthening member is 2.86 times of a non-strengthened one. Ductile failure tends to happen for the strengthened member. All these concluded that the technique of FRP fast strengthening steel members is feasible and effective.