diff --git a/turbo/jsonrpc/otterscan_api.go b/turbo/jsonrpc/otterscan_api.go
index 76072b3dd78..161a8d1388e 100644
--- a/turbo/jsonrpc/otterscan_api.go
+++ b/turbo/jsonrpc/otterscan_api.go
@@ -67,9 +67,6 @@ type OtterscanAPI interface {
 	GetTransactionError(ctx context.Context, hash common.Hash) (hexutility.Bytes, error)
 	GetTransactionBySenderAndNonce(ctx context.Context, addr common.Address, nonce uint64) (*common.Hash, error)
 	GetContractCreator(ctx context.Context, addr common.Address) (*ContractCreatorData, error)
-
-	// TODO: remove test
-	TxNum2Block(ctx context.Context, txNum uint64) (uint64, error)
 }
 
 type OtterscanAPIImpl struct {
@@ -86,24 +83,6 @@ func NewOtterscanAPI(base *BaseAPI, db kv.TemporalRoDB, maxPageSize uint64) *Ott
 	}
 }
 
-func (api *OtterscanAPIImpl) TxNum2Block(ctx context.Context, txNum uint64) (uint64, error) {
-	tx, err := api.db.BeginTemporalRo(ctx)
-	if err != nil {
-		return 0, err
-	}
-	defer tx.Rollback()
-
-	ok, blockNum, err := rawdbv3.TxNums.FindBlockNum(tx, txNum)
-	if !ok {
-		return 0, nil
-	}
-	if err != nil {
-		return 0, err
-	}
-
-	return blockNum, nil
-}
-
 func (api *OtterscanAPIImpl) GetApiLevel() uint8 {
 	return API_LEVEL
 }