They are pretty similar :) They are the same in this example: Prices go up each day. Prices go up every day. This means that the action takes place every single day in succession. But in this example, "each day" can mean only on certain days. "For each day that it is raining, I stay at home". So you don't stay at home every day, but on the days that it is raining, you stay at home. Read more about each and every here: http://www.englishclub.com/grammar/adjectives-determiners-each-every.htm

i think that there is no difference in meaning. when you use in sentence, they are differ.

There is no real difference. "Each" implies more importance on the objects being identified separately. "Every" implies more importance on including all of the objects. For example "Tell each person the king is dead" - This would imply that you should talk to each individual separately to give them the information. That is, if there are 10 people, you would be more likely to say "The king is dead" 10 times. "Tell every person the news" - This implies that you should make certain that you do not miss anyone. You might gather all 10 people and say "The king is dead" just once.