diff --git a/x/staking/keeper/delegation.go b/x/staking/keeper/delegation.go
index 7581eb82f5..572c4d4b00 100644
--- a/x/staking/keeper/delegation.go
+++ b/x/staking/keeper/delegation.go
@@ -30,10 +30,9 @@ func (k Keeper) UpdateProxy(ctx sdk.Context, delegator types.Delegator, tokens s
 // Delegate handles the process of delegating
 func (k Keeper) Delegate(ctx sdk.Context, delAddr sdk.AccAddress, token sdk.DecCoin) sdk.Error {
 
-	delQuantity := token.Amount
-
-	if delQuantity.LT(k.ParamsMinDelegation(ctx)) {
-		return types.ErrInvaildQuantity(types.DefaultCodespace, delQuantity.String())
+	delQuantity, minDelLimit := token.Amount, k.ParamsMinDelegation(ctx)
+	if delQuantity.LT(minDelLimit) {
+		return types.ErrInsufficientQuantity(types.DefaultCodespace, delQuantity.String(), minDelLimit.String())
 	}
 
 	// 1.transfer account's okt into bondPool
@@ -67,10 +66,13 @@ func (k Keeper) Undelegate(ctx sdk.Context, delAddr sdk.AccAddress, token sdk.De
 	if !found {
 		return time.Time{}, types.ErrNoDelegationVote(types.DefaultCodespace, delAddr.String())
 	}
-	quantity := token.Amount
-	if quantity.LT(k.ParamsMinDelegation(ctx)) || delegator.Tokens.LT(quantity) {
-		return time.Time{}, types.ErrInvaildQuantity(types.DefaultCodespace, quantity.String())
+	quantity, minDelLimit := token.Amount, k.ParamsMinDelegation(ctx)
+	if quantity.LT(minDelLimit) {
+		return time.Time{}, types.ErrInsufficientQuantity(types.DefaultCodespace, quantity.String(), minDelLimit.String())
+	} else if delegator.Tokens.LT(quantity) {
+		return time.Time{}, types.ErrInsufficientDelegation(types.DefaultCodespace, quantity.String(), delegator.Tokens.String())
 	}
+
 	// 1.some okt transfer bondPool into unbondPool
 	k.bondedTokensToNotBonded(ctx, token)
 
diff --git a/x/staking/types/errors.go b/x/staking/types/errors.go
index 29c30229a7..e4f3f3266e 100644
--- a/x/staking/types/errors.go
+++ b/x/staking/types/errors.go
@@ -213,10 +213,16 @@ func ErrNotInDelegating(codespace sdk.CodespaceType, addr string) sdk.Error {
 		"failed. the addr %s is not in the status of undelegating", addr)
 }
 
-// ErrInvaildQuantity returns an error when the quantity is invalid
-func ErrInvaildQuantity(codespace sdk.CodespaceType, quantity string) sdk.Error {
+// ErrInsufficientDelegation returns an error when the delegation left is not enough for unbonding
+func ErrInsufficientDelegation(codespace sdk.CodespaceType, quantity, delLeft string) sdk.Error {
 	return sdk.NewError(codespace, CodeInvalidDelegation,
-		"failed. the quantity %s is invaild", quantity)
+		"failed. insufficient delegation. [delegation left]:%s, [quantity to unbond]:%s", delLeft, quantity)
+}
+
+// ErrInsufficientQuantity returns an error when the quantity is less than the min delegation limit
+func ErrInsufficientQuantity(codespace sdk.CodespaceType, quantity, minLimit string) sdk.Error {
+	return sdk.NewError(codespace, CodeInvalidDelegation,
+		"failed. insufficient quantity. [min limit]:%s, [quantity]:%s", minLimit, quantity)
 }
 
 // ErrInsufficientMinSelfDelegation returns an error when the msd is not enough