I/O PINS

I going to Used Leonardo Board in that digital pis are 20 but on the bord 14 pins are available So, how i can used other digital pins

Use the analogue pins as digital pins.

But realistically it's 18, since you probably want to leave digital 0 and 1 alone for comms.

AWOL:
Use the analogue pins as digital pins.

This only works for a digital input, right? Or is there some way that the analog outputs can be driven?

HankB:
This only works for a digital input, right? Or is there some way that the analog outputs can be driven?

"Analog pins" can be used like digital pins, as ("digital") inputs or ("digital") outputs. They are no "analog outputs" of course.
Take a look at: http://arduino.cc/en/Reference/PinMode:

The analog input pins can be used as digital pins, referred to as A0, A1, etc.

Thanks for pointing that out. I learned something new about the Arduino. I would have never have guessed that analog inputs could be configured as outputs.