diff --git a/misc/config_tools/schema/config.xsd b/misc/config_tools/schema/config.xsd
index 0aa4f1ebb..a81d212a8 100644
--- a/misc/config_tools/schema/config.xsd
+++ b/misc/config_tools/schema/config.xsd
@@ -172,6 +172,11 @@ If your VM is not a security VM, leave this option unchecked. </xs:documentation
         </xs:restriction>
       </xs:simpleType>
     </xs:element>
+    <xs:element name="MAX_PCI_BUS_NUM" type="xs:integer" default="0">
+      <xs:annotation acrn:views="">
+        <xs:documentation>Specify the maximum number of PCI buses. The default value is calculated from the board configuration file. Integer from 1 to 256.</xs:documentation>
+      </xs:annotation>
+    </xs:element>
     <xs:element name="MAX_PCI_DEV_NUM" default="96">
       <xs:annotation acrn:title="Max PCI devices" acrn:views="advanced"
                      acrn:errormsg="'required': 'must config the max number of PCI devices'">
diff --git a/misc/config_tools/static_allocators/board_capability.py b/misc/config_tools/static_allocators/board_capability.py
index 141afca9c..e03528a5e 100644
--- a/misc/config_tools/static_allocators/board_capability.py
+++ b/misc/config_tools/static_allocators/board_capability.py
@@ -4,7 +4,7 @@
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
-
+import logging
 import common
 
 def powerof2_roundup(value):
@@ -22,5 +22,14 @@ def create_max_ir_entries(scenario_etree, allocation_etree):
 
 def fn(board_etree, scenario_etree, allocation_etree):
     pci_bus_nums =  board_etree.xpath("//bus[@type='pci']/@address")
-    common.append_node("/acrn-config/platform/MAX_PCI_BUS_NUM", hex(max(map(lambda x: int(x, 16), pci_bus_nums)) + 1), allocation_etree)
+    calc_pci_bus_nums = (max(map(lambda x: int(x, 16), pci_bus_nums)) + 1)
+    user_def_pci_bus_nums = common.get_node(f"//MAX_PCI_BUS_NUM/text()", scenario_etree)
+    if user_def_pci_bus_nums == '0':
+        common.append_node("/acrn-config/platform/MAX_PCI_BUS_NUM", hex(calc_pci_bus_nums), allocation_etree)
+    else:
+        if calc_pci_bus_nums > int(user_def_pci_bus_nums):
+            logging.error(f"MAX_PCI_BUS_NUM should be greater than {calc_pci_bus_nums}")
+            sys.exit(1)
+        else:
+            common.append_node("/acrn-config/platform/MAX_PCI_BUS_NUM", hex(int(user_def_pci_bus_nums)), allocation_etree)
     create_max_ir_entries(scenario_etree, allocation_etree)