diff --git a/types/upgrade.go b/types/upgrade.go
index 263870973..5857a4c1f 100644
--- a/types/upgrade.go
+++ b/types/upgrade.go
@@ -4,6 +4,8 @@ import "fmt"
 
 var UpgradeMgr = NewUpgradeManager(UpgradeConfig{})
 
+const FixSignBytesOverflow = "FixSignBytesOverflow" // fix json unmarshal overflow when build SignBytes
+
 var MainNetConfig = UpgradeConfig{
 	HeightMap: map[string]int64{},
 }
diff --git a/types/utils.go b/types/utils.go
index 10ec85472..d880f9983 100644
--- a/types/utils.go
+++ b/types/utils.go
@@ -1,6 +1,7 @@
 package types
 
 import (
+	"bytes"
 	"encoding/json"
 	"time"
 
@@ -15,7 +16,14 @@ import (
 // If the passed JSON isn't valid it will return an error.
 func SortJSON(toSortJSON []byte) ([]byte, error) {
 	var c interface{}
-	err := json.Unmarshal(toSortJSON, &c)
+	var err error
+	if !IsUpgrade(FixSignBytesOverflow) {
+		err = json.Unmarshal(toSortJSON, &c)
+	} else {
+		decoder := json.NewDecoder(bytes.NewReader(toSortJSON))
+		decoder.UseNumber()
+		err = decoder.Decode(&c)
+	}
 	if err != nil {
 		return nil, err
 	}
diff --git a/types/utils_test.go b/types/utils_test.go
index 467669186..ef0b9ec68 100644
--- a/types/utils_test.go
+++ b/types/utils_test.go
@@ -45,6 +45,36 @@ func TestSortJSON(t *testing.T) {
 	}
 }
 
+func TestSortJSONOverflow(t *testing.T) {
+	UpgradeMgr.AddUpgradeHeight(FixSignBytesOverflow, 100)
+	UpgradeMgr.SetHeight(100)
+
+	cases := []struct {
+		unsortedJSON string
+		want         string
+		wantErr      bool
+	}{
+		// from the TXSpec:
+		{unsortedJSON: `{"chain_id":"test-chain-1","sequence":1,"msg_bytes":{"inputs":[{"address":"696E707574","coins":[{"amount":9007199326368011,"denom":"atom"}]}],"outputs":[{"address":"6F7574707574","coins":[{"amount":9007199326368011,"denom":"atom"}]}]},"alt_bytes":null}`,
+			want:    `{"alt_bytes":null,"chain_id":"test-chain-1","msg_bytes":{"inputs":[{"address":"696E707574","coins":[{"amount":9007199326368011,"denom":"atom"}]}],"outputs":[{"address":"6F7574707574","coins":[{"amount":9007199326368011,"denom":"atom"}]}]},"sequence":1}`,
+			wantErr: false},
+	}
+
+	for tcIndex, tc := range cases {
+		got, err := SortJSON([]byte(tc.unsortedJSON))
+		if tc.wantErr {
+			require.NotNil(t, err, "tc #%d", tcIndex)
+			require.Panics(t, func() { MustSortJSON([]byte(tc.unsortedJSON)) })
+		} else {
+			require.Nil(t, err, "tc #%d, err=%s", tcIndex, err)
+			require.NotPanics(t, func() { MustSortJSON([]byte(tc.unsortedJSON)) })
+			require.Equal(t, got, MustSortJSON([]byte(tc.unsortedJSON)))
+		}
+
+		require.Equal(t, string(got), tc.want)
+	}
+}
+
 func TestTimeFormatAndParse(t *testing.T) {
 	cases := []struct {
 		RFC3339NanoStr     string