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In order to study the degradation law of steel mechanical properties and seismic performance of frame joints with corrosion degree increased in the acidic atmospheric environment, the one directional tensile tests of 24 standard steel material specimens were performed and 12 beam-column joint specimens in different corrosion levels were tested under cyclic loading. Based on material test data, the linear regression relationship between the yield strength, ultimate strength, elastic modulus, elongation and weightlessness rate was established, the influences of different corrosion rates and loading systems on loading-displacement curve, skeleton curve, strength and stiffness degradation, deformability, hysteretic energy dissipation of steel frame joint were analyzed. The degradation laws of load carrying capacity, strength, stiffness and energy dissipation capacity of the corroded steel frame joint with the corrosion degree increased were established. The results show that corrosion has a significant impact on the damage pattern of steel frame joint. With the increase of corrosion degree, the energy dissipation of the specimens decreases gradually, the load carrying capacity falls sharply in the late loading stage and the brittle fracture occurs more obvious. With the increase of displacement amplitude and cycle number, the plastic deformation of steel frame joint is accumulated gradually, the stiffness and strength degradation is obvious. Under the same corrosion degree, the energy dissipation capacity of specimen with variable amplitude loading is the biggest of all, followed by the mixed loading, and the constant amplitude the minimum. The results can provide experimental support for the seismic fragility study of existing steel frame structure. [ABSTRACT FROM AUTHOR]