diff --git a/tools/codegen/src/ast/raw/mod.rs b/tools/codegen/src/ast/raw/mod.rs
index 6b97274..d0165f2 100644
--- a/tools/codegen/src/ast/raw/mod.rs
+++ b/tools/codegen/src/ast/raw/mod.rs
@@ -6,11 +6,24 @@ mod utils;
 
 #[derive(Debug, Default, Property)]
 pub(crate) struct Ast {
+    syntax_version: Option<SyntaxVersionStmt>,
     namespace: String,
     imports: Vec<ImportStmt>,
     decls: Vec<TopDecl>,
 }
 
+impl Default for SyntaxVersionStmt {
+    fn default() -> Self {
+        Self { major: 1, minor: 0 }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Property)]
+pub(crate) struct SyntaxVersionStmt {
+    major: usize,
+    minor: usize,
+}
+
 #[derive(Debug, Clone, Property)]
 pub(crate) struct ImportStmt {
     name: String,
diff --git a/tools/codegen/src/ast/raw/utils.rs b/tools/codegen/src/ast/raw/utils.rs
index e27735e..e5b14e1 100644
--- a/tools/codegen/src/ast/raw/utils.rs
+++ b/tools/codegen/src/ast/raw/utils.rs
@@ -3,6 +3,7 @@ use std::{ffi, fs, io::Read as _, path::Path, str::FromStr};
 use pest::{error::Error as PestError, iterators::Pairs, Parser as _};
 use same_file::is_same_file;
 
+use crate::ast::raw::SyntaxVersionStmt;
 use crate::{
     ast::raw as ast,
     parser,
@@ -184,6 +185,23 @@ impl parser::Parser {
                 panic!("grammar should have only one EOI");
             }
             match pair.as_rule() {
+                parser::Rule::syntax_version_stmt => {
+                    let mut pair = pair.into_inner();
+                    let syntax_version = SyntaxVersionStmt {
+                        major: pair.next_usize(),
+                        minor: pair.next_usize(),
+                    };
+                    pair.next_should_be_none();
+                    if ast.syntax_version.is_some() {
+                        // compare ast.syntax_version and syntax_version
+                        // panic if there is a conflict syntax_version
+                        if ast.syntax_version != Some(syntax_version) {
+                            panic!("all schema files' syntax version should be same");
+                        }
+                    } else {
+                        ast.syntax_version = Some(syntax_version);
+                    }
+                }
                 parser::Rule::import_stmt => {
                     let mut pair = pair.into_inner();
                     let node = pair.next_import(path, imported_depth);
@@ -265,6 +283,10 @@ impl parser::Parser {
         if !eoi {
             panic!("grammar should have only one EOI");
         }
+
+        if ast.syntax_version.is_none() {
+            ast.syntax_version = Some(SyntaxVersionStmt::default());
+        }
         Ok(())
     }
 }
diff --git a/tools/codegen/src/grammar.pest b/tools/codegen/src/grammar.pest
index 15c073b..4e1ef3b 100644
--- a/tools/codegen/src/grammar.pest
+++ b/tools/codegen/src/grammar.pest
@@ -78,8 +78,14 @@ path_super      =   @{ "../" }
 path            =   { path_super* ~ (identifier ~ "/")* ~ identifier }
 import_stmt     =   { "import" ~ (brk)+ ~ path ~ (brk)* ~ stmt_end }
 
+syntax_major_version = @{ digit* }
+syntax_minor_version = @{ digit* }
+syntax_version = _{ syntax_major_version ~ "." ~ syntax_minor_version }
+syntax_version_stmt = { "syntax" ~ (brk)* ~ "=" ~ (brk)* ~ syntax_version ~ (brk)* ~ stmt_end}
+
 grammar         =   {
                         SOI ~ (brk)* ~
+                            (syntax_version_stmt)? ~ (brk)* ~
                             (import_stmt ~ (brk)*)* ~
                                 decl_stmt ~
                             ((brk)* ~ decl_stmt)* ~ (brk)* ~