diff --git a/pkg/bbgo/session.go b/pkg/bbgo/session.go
index 28dde0584..fce711e46 100644
--- a/pkg/bbgo/session.go
+++ b/pkg/bbgo/session.go
@@ -17,6 +17,21 @@ import (
 	"github.com/c9s/bbgo/pkg/util"
 )
 
+var (
+	debugEWMA = false
+	debugSMA = false
+)
+
+func init() {
+	if v, ok := util.GetEnvVarBool("DEBUG_EWMA"); ok {
+		debugEWMA = v
+	}
+
+	if v, ok := util.GetEnvVarBool("DEBUG_SMA"); ok {
+		debugSMA = v
+	}
+}
+
 type StandardIndicatorSet struct {
 	Symbol string
 	// Standard indicators
@@ -45,9 +60,22 @@ func NewStandardIndicatorSet(symbol string, store *MarketDataStore) *StandardInd
 			iw := types.IntervalWindow{Interval: interval, Window: window}
 			set.sma[iw] = &indicator.SMA{IntervalWindow: iw}
 			set.sma[iw].Bind(store)
+			if debugSMA {
+				set.sma[iw].OnUpdate(func(value float64) {
+					log.Infof("%s SMA %s: %f", symbol, iw.String(), value)
+				})
+			}
 
 			set.ewma[iw] = &indicator.EWMA{IntervalWindow: iw}
 			set.ewma[iw].Bind(store)
+
+			// if debug ewma is enabled, we add the debug handler
+			if debugEWMA {
+				set.ewma[iw].OnUpdate(func(value float64) {
+					log.Infof("%s EWMA %s: %f", symbol, iw.String(), value)
+				})
+			}
+
 		}
 
 		// setup boll indicator, we may refactor boll indicator by subscribing SMA indicator,