I am going to visit china on business for 10 days. My employer is paying only USD100 per day. Is 100$ enough?

Depends on where you live, $100 is worth 700-800 RMB, which should get you $700-$800 worth of stuff in a medium sized city. Larger cities might be more expensive, but it's more than enough to live on if you don't need to pay for housing.

Well according to currency exchange, 100 dollars is about 719 Chinese Yuan Renminbi. I'm sure that's enough for meals and maybe transportation. Is he also paying for your hotel stay?

Your employer is very generous. USD100 is a lot of money in China, it equals to 700 RMB roughly. People earn about that amount in a month, some unskilled labour earn only 200-300 RMB monthly.
A meal cost you about 40 RMB , and you don't need to take public transport like buses and train, with that kind of money you can take a taxi wherever you want to go.

If your hotel is paid for, you should be fine. If your hotel is not paid for, $100 won't even cover a decent hotel in many cities in China.

USD 100.- not enough.

Well, what's the money for? What about the hotel? If hotel is already included, then that's ok. Otherwise, it wouldn't be enough!

I've lived here 10 years---this depends on where you are, and what you are supposed to do with that $100. If it is just for you--meals, transporation, etc, it should be plenty (except maybe in Hong Kong). If you are also expected to entertain on that budget, or pay for your hotel, you will not be able to. (One meal for business entertainment could easily cost you the whole $100, and hotels in Beijing/Shanghai will run you the whole budget a night easily.). But if it is just for you---For Hong Kong, this is not enough. For Beijing, Shanghai, Guangzhou, etc, it's a little more than enough. For smaller cities, it's way more than enough.

I'll give you some Beijing stats that might help you:

Taxi--budget about $2.50-3.00 for each trip you take in one, for around town. If you have to go all the way across town frequently, or go outside the city, budget twice that much.

Sundries--bottle of water, budget $.70; phone card back home (for 40 minutes, and these are much cheaper than calling from your hotel) budget $14. (You can get them much cheaper, but only if you know exactly where to go). Coffee and scone at Starbucks, budget $7.

Meals (all prices for one person)--McDonalds--about $3.00 for a value meal. Pizza Hut--$13 a person. Chinese (local normal restaurant, enough for one, not fancy places or hotel restaurants)--$4-6. Fancy Chinese or hotel restaurants--$13-20.

Hope this helps!

oh my gosh. you should be happy.
100 american would be more than enough.
well it kinda depends on where you plan on eating. i like to eat street food. i wouldn't waste my money on mcdonalds.
its the same everywhere in the world.

You'll be more than OK with that. (Assuming that your boss is paying for hotel separately.) Might find more information that could help you at www.smartchinasourcing.com. Don't know if they have any advice on this particular topic but they do cover a lot of other aspects of doing business in China (like how to deal with cultural differences!)

a lot of people get$100 for a month a

yes enough.