Firstly

test of axially loaded recycled aggregate concrete filled steel tube stub columns after high temperatures was carried out.Based on the analysis of the test results

the stress-strain model of core recycled aggregate concrete（RAC） after high temperatures was suggested

and the effects of the recycled coarse aggregate（RCA） replacement ratio and the maximum suffered temperature were considered in the model.Secondly

the load-deformation relation of RAC filled steel tube stub columns after high temperatures was calculated using the numerical method

and the numerical results agreed well with the experimental results.Finally

based on the theoretical model

the influences of RCA replacement ratio

maximum suffered temperature and confinement factor on the strength index of RAC filled steel tube stub columns after high temperatures were calculated

and the simplified formulae for the strength index of RAC filled steel tube stub columns after high temperatures were proposed.The predicted bearing capacity of RAC filled steel tube stub columns after high temperatures generally agreed well with the test results. The results in this paper may throw light on practical engineering.