The　reinforcement　and　repair　process　of　earthquake-damaged　building　is　a　key　factor　in　improving　its　seismic　capability.　A　thorough　understanding　of　reinforcement　methods　and　processes　will　aid　in　repairing　earthquake-damaged　buildings　and　improving　seismic　capability.　Based　on　the　development　concept　of　digital　twin　and　mixed　reality,　an　intelligent　guidance　method　suitable　for　earthquake-damaged　building　reinforcement　was　proposed,　and　a　guidance　reinforcement　system　based　on　digital　twin　and　mixed　reality　was　established.　Firstly,　a　digital　twin　model　was　built,　including　four　operating　spaces,　operations　in　each　space　and　twin　data.　Twin　databases　were　built　to　manage　large　amounts　of　data.　In　order　to　realize　bidirectional　mapping　between　physical　space　and　virtual　space,　a　human-computer　interaction　mechanism　suitable　for　mixed　reality　was　developed　with　the　help　of　HoloLens.　Finally,　to　evaluate　the　practicability　and　effectiveness　of　the　proposed　method,　an　experimental　scenario　was　prepared　for　usability　testing.　Twenty　participants　were　recruited　using　purposive　sampling,　and　they　performed　the　same　reinforcement　task　under　the　guidance　of　the　2D　paper　version　or　the　DTMR-DRS　module.　Their　time　to　complete　the　task,　error　rate　were　recorded　and　they　were　asked　to　fill　out　a　questionnaire.The　results　show　that　compared　with　traditional　paper　documents,　the　developed　system　DTMR-DRS　transmits　information　more　quickly.　The　display　of　text-voice-video-model　also　makes　the　construction　guidance　more　stereoscopic　and　comprehensive.　It　has　significant　advantages　in　helping　reinforcement　constructors　to　improve　work　efficiency　and　reduce　rework　rates,　making　contribution　to　the　research　of　related　knowledge　systems.　©　2022,　Editorial　Department　of　Journal　of　Architecture　and　Civil　Engineering.　All　rights　reserved.