The　isocyanate　system　could　directly　react　with　water　in　the　air　to　cure　without　adding　curing　agent,　thus　realizing　self-healing,　but　it　also　limited　its　water　resistance　in　humid　environment.　In　this　study,　polydopamine　was　deposited　on　the　surface　of　isocyanate　microcapsules　to　improve　their　water　resistance.　Final　microcapsules　had　a　diameter　of　322.1　+/-　69.8　mu　m,　a　shell　thickness　of　6.5　+/-　0.3　mu　m　and　a　core　content　of　83.3　%　+/-　2.4　wt%.　The　optimum　synthesis　parameters　for　polydopamine　doposition　was　dopamine　concentration　of　8.0　mg/ml,　agitation　rate　of　300　rpm,　and　reaction　duration　of　24　h.　After　being　immersed　in　ambient　water　for　28　days,　the　redisual　core　material　of　final　microcapsules　still　remained　at　15.0　wt%.　Besides,　the　final　microcapsules　started　to　decompose　at　240.0　degrees　C,　indicating　good　thermal　stability.　The　study　also　investigated　the　influence　mechanism　of　microcapsules　strength　and　interfacial　strength　on　the　mechanical　properties　of　self-healing　cement　paste.　At　the　same　time,　the　total　porosity　of　self-healing　cement　paste　increased　under　higher　microcapsule　concentration.　In　addition,　the　self-healing　cement　paste　could　effectively　repair　cracks　with　width　of　about　100　mu　m,　showed　good　self-healing　ability.