you are taller than me or you are taller than I?
which pronoun is correct?if you are taller than I is correct, why we say she is
taller than him instead of he?

Question

you are taller than me or you are taller than I?
which pronoun is correct?if you are taller than I is correct, why we say she is
taller than him instead of he?

Answer

Both forms are used and both are considered correct.. 

You are taller than I..........is a short form of .....You are taller than I am. 
You are taller than me......is also correct. 

She is taller than he...... is a short form of.....She is taller than he is. 
She is taller than him.....is also correct.

Answer

"you are taller than me" is more correct I think.
we would not really say "you are taller than I"

Actually, I would probably phrase it "I am taller than you", or "you are shorter than me" 
(at 192cm, I think I am probably taller .... :)

There are lots of things in English that don't make any logical sense. Best just to learn how it is done.
formally, we say "can Fred and I can go now" but in spoken, we could say "can me and Fred go now", it's much less formal, but still common enough.

Answer

you are taller than me is the correct one.

ご自宅で快適に語学を学べるチャンスをお見逃しなく。経験豊富な語学講師陣の中からお選びいただき、今すぐ最初のレッスンにお申し込みください！