Later on he entered the service of King Hui of Wei 魏惠王 (better known as King Hui of Liang 梁惠王, r. 379-335). Envious of Sun Bin, who was a better strategist than himself, Pang Juan had Sun Bin come to Wei and accused him of some crime. Sun Bin was charged guilty and cut off his kneecaps.
In 354, Pang Juan led the army of Wei against the state of Zhao 趙, and one year later, he conquered Handan 邯鄲, the capital of Zhao. Shortly after his army was defeated by the army of Qi 齊, which was led by Tian Ji 田忌 and Sun Bin. He was taken captive, but soon released, and returned to Wei.
In 341, the army of Wei under the commmand of Pang Juan and Prince Shen 申 attacked the state of Han 韓, and again, relief troops from Qi were dispatched. In the battle of Maling 馬陵 (modern Daming 大名, Hebei) Sun Bin defeated the army of Wei, Pang Juan was again taken captive, and committed suicide.