many和much的区别主要是
1、many修饰复数可数名词，表许多；much修饰不可数名词，表量或程度。He has many friends, but few true ones.
There hasn't been much good weather recently.
2、many a：
many a和many同义，但语气比较强，并且要与单数名词及单数形动词连用。
Many a prisoner has been set free. (=Many prisoners have been set free.)
3、as many和so many均等于the same number of。 前有as, like时, 只用so many。
These are not all the books I have. These are as many more upstairs.
They worked like so many ants.
4、as much等于the same amount of, 表同量和同一事情。
He bought two pounds of sugar and as much tea. 〔同量)
I was not in the least surprised, for I had fully expected as much. 〔同一事情)
5、many和much之后不接名词时，作为代名词;另外much也可用副词。
Many of them were very tired.
I don't eat much for lunch.
He is much taller than I.
6、many修饰可数名词复数，如：There aremany people.
much修饰不可数名词复数，如：I have much money.
7、many作代词代表可数名词，如：Many of the students have great results.
much作代词代表不可数名词，如：Much of the air is fresh.
8、much还可以修饰动词，many不行。
如：I love you so much.
9、much还可以修饰比较级，many也不行。
如：He's much taller than her.
It's much more difficult than you thought.