diff --git a/misc/config_tools/schema/config.xsd b/misc/config_tools/schema/config.xsd
index 3b9fbd186..4047f7ca4 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">
         <xs:documentation>Specify the maximum number of PCI devices. This impacts the amount of memory used to maintain information about these PCI devices. The default value is calculated from the board configuration file. If you have PCI devices that were not detected by the Board Inspector, you may need to change this maximum value.</xs:documentation>
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)