I just want to replace 250 W Metal Halides which are installed at 4 Mtr. Height in my industry by putting appropriate capacity LED fixture. Pl. suggest :)

4 meter = 12.8 feet.

12 Ft is too low for a 250 MH fixture, depending on the type fixture. Is this a flood light or a downlight?

I suspect a flood light.

LED equals to 250 watt MH do not exist, yet, to my knowledge.

If this is a downlight, you can use something equal to a 175 watt MH:

http://www.lumec.com/pdf/series/LifeLED_brochure_an.pdf