diff --git a/api/app/lib/controllers/operationData/index.js b/api/app/lib/controllers/operationData/index.js
index 9b7ccae..6ff2d71 100644
--- a/api/app/lib/controllers/operationData/index.js
+++ b/api/app/lib/controllers/operationData/index.js
@@ -44,7 +44,7 @@ async function getSystemAvailability(ctx) {
    try {
       const res = await sequelize.query(
          `SELECT substring(to_char(w.wmonth,'yyyy-mm'),1,7)  wmonth,
-         COALESCE((w.seconds-e.counts)/w.seconds,0) ability
+         COALESCE((w.seconds-e.counts)/w.seconds,1) ability
          from (
             SELECT to_char(maintenance_record.occurrence_time, 'yyyy-MM') months,
                SUM(maintenance_record.interrupt_duration) counts