diff --git a/packages/rpc/src/Base/index.ts b/packages/rpc/src/Base/index.ts
index 542b6c51f..2b85c2dc1 100644
--- a/packages/rpc/src/Base/index.ts
+++ b/packages/rpc/src/Base/index.ts
@@ -29,6 +29,12 @@ export interface GetTransaction {
   (hash: CKBComponents.Hash, verbosity: "0x2", onlyCommitted?: boolean): Promise<CKBComponents.TransactionWithStatus>;
 }
 
+// prettier-ignore
+export interface GetHeader<Q> {
+  (query: Q, verbosity?: "0x1"): Promise<CKBComponents.BlockHeader>;
+  (query: Q, verbosity: "0x0"): Promise<string>;
+}
+
 export interface Base {
   /* Chain */
 
@@ -91,9 +97,7 @@ export interface Base {
    * @description Returns the information about a block header by hash.
    * @params {Promise<string>} block hash
    */
-  getHeader: (
-    blockHash: CKBComponents.Hash
-  ) => Promise<CKBComponents.BlockHeader>;
+  getHeader: GetHeader<CKBComponents.Hash>;
 
   /**
    * @method getHeaderByNumber
@@ -101,9 +105,7 @@ export interface Base {
    * @description Returns the information about a block header by block number
    * @params {Promise<string>} block number
    */
-  getHeaderByNumber: (
-    blockNumber: CKBComponents.BlockNumber | bigint
-  ) => Promise<CKBComponents.BlockHeader>;
+  getHeaderByNumber: GetHeader<CKBComponents.BlockNumber | bigint>;
 
   /**
    * @method getLiveCell
diff --git a/packages/rpc/src/resultFormatter.ts b/packages/rpc/src/resultFormatter.ts
index 4e8a8fa7c..b38147647 100644
--- a/packages/rpc/src/resultFormatter.ts
+++ b/packages/rpc/src/resultFormatter.ts
@@ -24,7 +24,13 @@ const toNullable =
 const toNumber = (number: RPC.BlockNumber): CKBComponents.BlockNumber =>
   number.toString();
 const toHash = (hash: RPC.Hash256): CKBComponents.Hash256 => hash;
-const toHeader = (header: RPC.Header): CKBComponents.BlockHeader => {
+
+function toHeader(header: RPC.Header): CKBComponents.BlockHeader;
+function toHeader(header: string): string;
+function toHeader(
+  header: string | RPC.Header
+): string | CKBComponents.BlockHeader {
+  if (typeof header === "string") return header;
   if (!header) return header;
   const {
     compact_target: compactTarget,
@@ -42,7 +48,8 @@ const toHeader = (header: RPC.Header): CKBComponents.BlockHeader => {
     extraHash,
     ...rest,
   };
-};
+}
+
 const toScript = (script: RPC.Script): CKBComponents.Script => {
   if (!script) return script;
   const { code_hash: codeHash, hash_type: hashType, ...rest } = script;
diff --git a/packages/rpc/src/types/api.ts b/packages/rpc/src/types/api.ts
index 843d606c9..f53c4e36c 100644
--- a/packages/rpc/src/types/api.ts
+++ b/packages/rpc/src/types/api.ts
@@ -74,7 +74,7 @@ export namespace CKBComponents {
   export type Transaction = Required<api.Transaction>;
   export type TransactionWithStatus<Tx = Transaction> =
     api.TransactionWithStatus<Tx>;
-  export type BlockHeader = api.Header;
+  export type BlockHeader<T = api.Header> = T;
   export type Block = api.Block;
   export type UncleBlock = api.UncleBlock;
   export type LiveCell = api.LiveCell;