The　medium　voltage　distribution　lines　with　long　power　supply　radius　and　broad　load　fluctuations,　because　of　the　larger　voltage　loss　in　the　line,　often　result　in　low　voltage　and　voltage　fluctuation　in　the　load-side,　which　is　difficult　to　meet　the　requirements　of　voltage　quality.　The　compensation　of　capacitor　is　calculated　precisely　under　different　loads,　and　then　the　maximum　transmission　capacity　of　the　medium　voltage　radial　line　with　the　series　capacitance　compensation　can　be　gotten　when　the　voltage　of　the　end　line　is　stable.　Simulation　using　Matlab/Simulink　is　carried　out　and　the　results　verify　the　correctness　of　this　calculation.　The　series　capacitance　compensator　is　applied　to　10　kV　radiation　line　and　its　normal　operation　and　stable　load-side　voltage　verify　the　practicality　of　series　capacitance　compensation.