When I turn my circuit on the LED turns on but even in the dark the LED is still on.
Can someone help me?
Pin 6 is floating.. connect pin 6 with pin 2. (By doing so you are connecting inverting and non-inverting comparator together.
and change the 4.7K resistor with 1M ohm variable resistor .
Slowly change the resistance and adjust the sensitivity based on your ambient light.
I suspect you have misunderstood how the 555 functions. Because there is a latch (flipflop) in the 555, an input on pin 2 can only set the latch; it cannot reset it - an input on pin 6 does the reset.
What you need is an analog comparator - google "light-activated switch". A dark-activated switch just needs the inputs reversed.