The joints of steel and concrete (JSC) is the key substructure to composite bridge, the method of condition monitoring and safety assessment were carried out for JSC with perfobond shear connectors (PBL) and local prestressed tendon in largespan bridge. According to the damage mechanism of JSC, new monitoring parameters were proposed. The sensor location layout and the assessment thresholds of PBL were addressed with the consideration of the disadvantage influences of environment, load and concrete creep to local prestressed loss assessment and validated by the static load experiment. Compared the experimental results with field monitoring data, it was found that the new monitoring parameters and new assessment method were feasible and can be used as reference to the same type connectors in largespan bridges.