diff --git a/aspect/assembly/aspect/aspect.ts b/aspect/assembly/aspect/aspect.ts
index 831ce19..f85c65e 100644
--- a/aspect/assembly/aspect/aspect.ts
+++ b/aspect/assembly/aspect/aspect.ts
@@ -90,14 +90,13 @@ export class Aspect implements IAspectTransaction, IAspectOperation, ITransactio
             "illegal session key scope, method isn't allowed. actual is " + method + ". detail: " + sys.utils.uint8ArrayToHex(ctx.tx.content.unwrap().input));
 
         // 4. verify expire block height
-        // const response = sys.hostApi.runtimeContext.get("tx^context");
-        // sys.require(response.result!.success, "get tx context fail");
-
-        // let tx = Protobuf.decode<EthTransaction>(response.data!.value, EthTransaction.decode)
+        const response = sys.hostApi.runtimeContext.get("block^header^0");
         
+        var ethBlockHeader = Protobuf.decode<EthBlockHeader>(response.data!.value, EthBlockHeader.decode);
+
         // const currentBlockHeight = ctx.tx.content.unwrap().blockNumber;
         const expireBlockHeight = sKeyObj.getExpireBlockHeight();
-        const currentBlockHeight = expireBlockHeight - 1 ;
+        const currentBlockHeight = ethBlockHeader.number + 1;
         sys.require(currentBlockHeight <= expireBlockHeight,
             "session key has expired; " + expireBlockHeight.toString() + " < " + currentBlockHeight.toString());
 
diff --git a/aspect/tests/test_tx.cjs b/aspect/tests/test_tx.cjs
index 109fd0a..02fb30e 100644
--- a/aspect/tests/test_tx.cjs
+++ b/aspect/tests/test_tx.cjs
@@ -185,15 +185,16 @@ async function f() {
         "// ******************************************\n\n");
 
     let currentBlockHeight = await web3.eth.getBlockNumber();
-    let expireBlockHeight = currentBlockHeight + 20; // ~10s
-
+    console.log("currentBlockHeight :", currentBlockHeight);
+    let expireBlockHeight = currentBlockHeight + 10; // ~10s
     // let op = "0x0001" + sKey + sKeyContract + "0001" + contractCallMethod + expireBlockHeight;
     let op =
         "0x0001"
         + sKey
         + sKeyContract
         + "0001" + contractCallMethod
-        + web3.eth.abi.encodeParameter('uint256', expireBlockHeight).slice(48, 64);
+        + rmPrefix(web3.eth.abi.encodeParameter('uint256', expireBlockHeight)).slice(48, 64);
+
     let sessionKeyRegData = aspect.operation(op).encodeABI();
     console.log("op: ", op);
     console.log("calldata: ", sessionKeyRegData);