Three full-featured reinforced interior joints of enhanced recycled aggregate concrete(EC-RAC) frame were considered in the low-cyclic loading test. The evolution process of seismic damage was studied, in which actual damage state and damage index were also determined. Meanwhile, a modified Park-Ang dual-parameter damage model was proposed, since the traditional model could not accurately describe the damage evolution and cumulative behavior of the EC-RAC frame joints after loading displacement greater than 100mm. The coefficients of fiber term, displacement term and energy term were fitted based on the above test results. Finally, taking HF-RAC2 as an example, the error of the damage index was analyzed based on the developed model. The results show that the average error is within 6%, which means the damage model can be applied to the EC-RAC frame joints for seismic damage and evaluation analysis.