diff --git a/api/dbus/org.desktopspec.ApplicationManager1.Instance.xml b/api/dbus/org.desktopspec.ApplicationManager1.Instance.xml
index d8eadff..2292a4e 100644
--- a/api/dbus/org.desktopspec.ApplicationManager1.Instance.xml
+++ b/api/dbus/org.desktopspec.ApplicationManager1.Instance.xml
@@ -41,5 +41,12 @@
                        to which the instance belonged has been removed."
             />
         </property>
+        <method name="KillAll">
+            <arg type="i" name="signal" direction="in"/> 
+            <annotation name="org.freedesktop.DBus.Description" 
+                        value="Force kill this instance.
+                                ATTENTION: All processes which launched by 
+                                this instance will be killed." />
+        </method>
     </interface>
 </node>
diff --git a/src/constant.h b/src/constant.h
index 4f3e707..8f65cc8 100644
--- a/src/constant.h
+++ b/src/constant.h
@@ -8,6 +8,7 @@
 constexpr auto SystemdService = u8"org.freedesktop.systemd1";
 constexpr auto SystemdObjectPath = u8"/org/freedesktop/systemd1";
 constexpr auto SystemdInterfaceName = u8"org.freedesktop.systemd1.Manager";
+constexpr auto SystemdUnitInterfaceName = u8"org.freedesktop.systemd1.Unit";
 constexpr auto DDEApplicationManager1ServiceName =
 #ifdef DDE_AM_USE_DEBUG_DBUS_NAME
     u8"org.desktopspec.debug.ApplicationManager1";
diff --git a/src/dbus/instanceservice.cpp b/src/dbus/instanceservice.cpp
index 21231de..549d7cc 100644
--- a/src/dbus/instanceservice.cpp
+++ b/src/dbus/instanceservice.cpp
@@ -3,8 +3,10 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 
 #include "dbus/instanceservice.h"
+#include "constant.h"
 #include "propertiesForwarder.h"
-#include <QCoreApplication>
+#include <QDBusMessage>
+#include "global.h"
 
 InstanceService::InstanceService(QString instanceId, QString application, QString systemdUnitPath, QString launcher)
     : m_Launcher(std::move(launcher))
@@ -16,3 +18,18 @@ InstanceService::InstanceService(QString instanceId, QString application, QStrin
 }
 
 InstanceService::~InstanceService() = default;
+
+void InstanceService::KillAll(int signal)
+{
+    auto killMsg = QDBusMessage::createMethodCall(SystemdService, m_SystemdUnitPath.path(), SystemdUnitInterfaceName, "Kill");
+    killMsg << QString{"all"} << signal;
+
+    auto &con = ApplicationManager1DBus::instance().globalDestBus();
+    auto reply = con.call(killMsg);
+
+    if (reply.type() == QDBusMessage::ReplyMessage) {
+        return;
+    }
+
+    sendErrorReply(reply.errorName(), reply.errorMessage());
+}
diff --git a/src/dbus/instanceservice.h b/src/dbus/instanceservice.h
index 95c7c2c..c47ba34 100644
--- a/src/dbus/instanceservice.h
+++ b/src/dbus/instanceservice.h
@@ -7,8 +7,9 @@
 
 #include <QObject>
 #include <QDBusObjectPath>
+#include <QDBusContext>
 
-class InstanceService : public QObject
+class InstanceService : public QObject, protected QDBusContext
 {
     Q_OBJECT
 public:
@@ -25,6 +26,9 @@ public:
 
     [[nodiscard]] const QString &instanceId() const noexcept { return m_instanceId; }
 
+public Q_SLOTS:
+    void KillAll(int signal);
+
 Q_SIGNALS:
     void orphanedChanged();