Okay, this is much better, content-wise. You have enough material, you just need to refine your logic a little bit:
To execute some of criminals will not make our lives more secure than before. People are facing a number of crimes such as robbery and assault on the streets which are putting our lives into more risks.
How does your second sentence here support your first one?
However, some countries such as Iran, China and a part of United States stil put capital punishment into practise.
Do they implement it in the same way? Does the way it is implemented have an effect on its effectiveness as a deterrent?
Your third paragraph is really quite strong, as far as content goes.
However, supporting to execute some criminals in order to make room for more does not include a rational point of view.
Why not? Seems perfectly rational to me. You can argue that one should not do this, but it is not self-evident that the course of action you have outlined here would be ineffective.
Moreover executing them will not make our lives more secure.
Only your third paragraph really argued this. Perhaps you could strengthen your essay more by replacing your fourth paragraph with one that discusses statistics involving crime rates and death penalties. Also, the opposing argument, which you might want to deal with, lies in the argument advanced by the hangman in the novel Going Postal
, in which he opines that, while he has no statistical evidence to show that the death penalty deters crime, he supports it because he has never had to hang anyone more than once, and so figures that the death penalty must be cutting down dramatically on recidivism rates.