Adaptive　backstepping　controller　of　cascaded　static　synchronous　compensator　(STATCOM)　was　proposed　in　this　paper　considering　the　nonlinear　characteristic　of　cascaded　STATCOM　system.　The　controller　obtained　virtual　control　input　of　cascaded　STATCOM　by　adopting　the　recursive　idea　of　backstepping.　It　designed　the　system　interim　control　rate　according　to　the　principle　of　certainty　equivalence　principle.　Using　the　above　system　interim　control　rate,　the　design　of　voltage　controller　was　completed　and　the　Lyapunov　equation　of　cascaded　STATCOM　system　was　set　up.　Using　the　Lyapunov　asymptotic　stability　principle,　the　control　inputs　and　adaptive　rate　of　system　parameters　to　ensure　the　stability　of　cascaded　STATCOM　were　obtained.　The　correctness　and　effectiveness　of　adaptive　backstepping　controller　was　validated　through　experiments.　©　2017,　The　editorial　office　of　Transaction　of　China　Electrotechnical　Society.　All　right　reserved.