The article is a study on the Union General, Ulysses S. Grant, and his military leadership, especially focusing on his Vicksburg campaign of 1863. At the strategic level it was of vital importance to recognize the strategic value of the Western Theatre in the American Civil War. Like other historians, I hold the view that his Vicksburg campaign was the turning point in the American Civil War. Many historians agree that Grant`s Vicksburg campaign could be regarded as his masterpiece in his military career. The Vicksburg campaign was one of the most brilliant operations in the military history, because he had conducted it with excellent maneuvering and encirclement operations with few casualties. Thus, Grant`s western campaigns might prove significant as a study in the field of the American military history. How could Grant defeat the Southern Confederate armies and receive the unconditional surrender of General Pemberton? Grant avoided the frontal attacks to the strong defense of Vicksburg after his several attacks had failed. Late April 1983, he crossed the Mississippi River below the city and marched to Jackson and defeated Johnston`s army. Grant succeeded to divide the Confederate armies and completely disabled Johnston`s army to assist Pemberton`s army. Grant pushed Pemberton`s army into Vicksburg and finally encircled the city for seven weeks from the middle of May in order to avoid heavy casualties. Meanwhile, without the support of General Johnston`s army outside the city, Pemberton`s army was on the verge of starvation. On July 4, 1863, Pemberton had to surrender unconditionally with his thirty-one thousand soldiers. Grant`s strategic boldness on not concerning himself about the conventional supply line came from his bold character and unexpected imagination as he had discarded an old Jomini`s maxim that the advance of a massive army requires a full supply lines and communications. None of his subordinates had firm confidence in Grant`s bold campaign plan. Throughout his entire operations of the Vicksburg campaign, Grant could be able to demonstrated a command of complete unity while conducting his campaigns and leading his corps in spite of his personal conflicts with ambitious General McClernand. Consequently, the success of Grant`s Vicksburg campaign resulted in dividing the Confederate nation into two and deeply isolated the southern economy. The Lincoln administration finally found to mark U. Grant as Robert Lee`s rival and recognized him as a strong and able military leader who could end the civil war.