firstly i dunno if there is thread as same as me ..but...i want to ask what is the different between 1st , 2nd, 3rd captain and so on..:)

Well, they are all different people. They all have different attacks, different jobs, and lead teams, or squads. THere are also vice captains too.

1st Division Captain:
Yamamoto Genryuusai Shigekuni

2nd Division Captain:
Soi Fong
2nd Division Vice Captain:
Ohmaeda Marechiyo

3rd Division Captain:
Ichimaru Gin
3rd Division Vice Captain:
Kira Izuru

4th Division Captain:
Unohana Retsu
4th Division Vice Captain:
Kotetsu Isane

5th Division Captain:
Aizen Sousuke
5th Division Vice Captain:
Hinamori Momo

6th Division Captain:
Kuchiki Byakuya
6th Division Vice Captain:
Abarai Renji

7th Division Captain:
Komamura Sajin
7th Division Vice Captain:
Iba Tetsuzaemo

8th Division Captain:
Kyouraku Shunsui
8th Division Vice Captain:
Ise Nanao

9th Division Captain:
Tousen Kaname
9th Division Vice Captain:
Hisagi Shuuhei

10th Division Captain:
Hitsugaya Toushiro
10th Division Vice Captain:
Matsumoto Rangiku

11th Division Captain:
Zaraki Kenpachi
11th Division Vice Captain:
Kusajishi Yachiru

12th Division Captain:
Kurotsuchi Mayuri
12th Division Vice Captain:
Kurotsuchi Nemu

13th Division Captain:
Ukitake Juushiro
13th Division Vice Captain:
Shiba Kaien (deceased)

each group has a certain trait of job to do. not all groups are the same. like one heals and one fights and one investigates.