有区别。
Four Star General
Only officers who show great leadership and loyalty become four-star generals.
Three Star General
An officer in the Army, Air Force, or Marines who is above the rank of Major is a Three Star General.
Major General
Commands a division which is 10,000 to 15,000 soldiers.
Brigadier General
Commands a brigade within a division.
Colonel
Usually commands a regiment within a division.
Lieutenant Colonel
Usually commands a battalion made up of 300 to 1,000 soldiers. A battalion is within a regiment.
Major
Serves as a staff officer to a regiment or division commander.
Captain
A captain usually commands a company with a battalion.
First Lieutenant
May command platoons or companies.
Second Lieutenant
Lowest ranking commissioned officer.
Sergeant Major of the Army
Highest rank for a soldier.
Command Sergeant
Carries out standards, performances, training, and conduct to soldiers.
Sergeant Major
The key enlisted member of a battalion.
Master Sergeant
The lead non-commissioned officer at the battalion and sometimes higher levels.
Sergeant First Class
Most candidates have at least 15 years experience. Referred to as Senior NCO’s or Non-Commissioned Officers.
Staff Sergeant
Has more time and experience in the Army than the Sergeant.
Sergeant
Non Commissioned Officer above a Corporal.
Corporal
Lowest non-commissioned officer, often commands a squad.
Private First Class
Grade above private.
Private
lowest rank of enlisted men.
参考资料：http://www.promotega.org/fld00019/rankings.htm