root.state('zommed') code example
Example 1: Tkinter maximise window
import Tkinter
MyRoot = Tkinter.Tk()
MyRoot.state("zoomed")
MyRoot.mainloop()
Example 2: Tkinter maximise window
root = Tk()
w, h = root.winfo_screenwidth(), root.winfo_screenheight()
root.geometry("%dx%d+0+0" % (w, h))