你可以使用Django消息框架来实现。

from django.contrib import messages

class MyAdminSite(AdminSite):
    def each_context(self, request):
        messages.add_message(request, messages.INFO, 'Hello world.')
        return super().each_context(request)

更多信息在此：https://docs.djangoproject.com/en/4.1/ref/contrib/messages/#adding-a-message
AdminSite更多信息：https://docs.djangoproject.com/en/4.1/ref/contrib/admin/#adminsite-objects