During his stay in War of Resistance against Japanese Aggression, Wang Jinshan successively served as deputy head of the Eighth Route Army (772) and head of the Eighth Route Army (769), taking part in various battles, ambushing Shanxi devils and attacking Japanese troops. In order to break through the enemy, Wang Jinshan led soldiers to annihilate more than 300 Japanese troops. The battle lasted for a day and a night, and many Japanese equipment and weapons were seized. Then more than 400 Japanese troops were annihilated in the same place. This battle greatly improved the equipment of the Eighth Route Army.
After World War II, Wang Jinshan participated in Shangdang Campaign, Huaihai Campaign and Dabie Mountain. In the 1950s, he participated in the War to Resist US Aggression and Aid Korea and won many honorary awards, as well as the Medal of Independence and Freedom and the Medal of Liberation.