last two months i submit 400 directories for one website..but i did not receive even one back link now what i do anyone explain me . and another one doubt how many directory we submit per day maximum any limitation?

Bear in mind that Google most likely won't discover all your directory backlinks at once. (Infact it will most likely discover them very slowly) To be honest, I don't  worry much about number of directories per day, but if you are using a program that can schedule it for you, maybe 100 a day.

It helps with directory submissions if you are submitting a domain address.

i am agree with admin directory submissions give slowly result. they approved slowly so 100 directories submission may have worth. well i am using social bookmarking sites i thinks its better we can get traffic as well as back links.

Directory submission take some time to approved. I think directory submission is one of the best way to improve traffic as well as backlinks for the site.

You should search instant approved directory sites. In general directory submission takes some time to get approval.

Today that there are lots of new trends on how to build backlinks most of the directories are not updated or not in use. So you must take a little bit of checking if the directory still works. Before you submit your site there.

you have done directory upto 400.. in which how many approved... because you will get back link when you have approved directory.