FramelessWindowHint

__author__ = 'Administrator'

from PyQt4 import QtGui,QtCore,Qt

from sys import argv

app = QtGui.QApplication(argv)

widget = QtGui.QWidget()

widget.resize(250,300)

widget.setGeometry(250,300,300,300)

widget.setWindowTitle("a window title")

widget.setWindowFlags(QtCore.Qt.FramelessWindowHint)

widget.show()

app.exec_()