A quasi-static loading test has been carried out on one RC frame joint with different seismic damage degrees strengthened by HPFL (high performance ferrocement laminates) and a comparative frame joint; meanwhile, a finite element numerical simulation analysis has been carried out by using the ANSYS finite element numerical simulation analysis, followed by a research conducted on the improvement of seismic performance of reinforced concrete frame joints strengthened by HPFL under such different earthquake damage conditions as failure mode, energy dissipation capacity, bearing capacity, ductility, stiffness degradation, etc.