Is 2500 US Dollar ok?

I got job in japan with the package of 2500 US dollar.Can i able to survive in japan and can i able to save money OR do i need to demand more wages.Kindly guide me.

Why is it in US dollar? How much in Japanese yen?

Depends on a few factors:

1. Location (rent especially plays a big part)
2. Your lifestyle
3. Single or married

But to answer your question anyway, it's a typical entry wage, enough for a low-middle spending, single person with no or minimal debts to pay off.

In yen its around 2,95000 to 300000.

Am single.can I save at least 20000 rupee per month.

Stick to one currency so we can figure out what you're trying to accomplish.

As it was pointed out, it depends on your lifestyle and your location. If you're the type to go out to bars all the time, then maybe you won't save much. If you're living in like central Tokyo I'm sure that rent'll be much higher than say a place in Saitama, for example. If you're in the inaka you could probably save a bit.

Do they give you many rent or transportation allowance? If not it's going to be tight in a big city such as Tokyo.

For single with the remuneration mentioned above saving of 30K-50K Yen is doable. It all depend on your lifestyle as long as you dont live an expat lifestyle.