A capacitor detection system and a passive-type pin-diverging module thereof are disclosed. The passive-type pin-diverging module is applied to two conductive pins of a capacitor, including a base structure and a rotatable structure. The rotatable structure is rotatably disposed on the base structure, and the rotatable structure has a curved surface. The two conductive pins of the capacitor respectively pass through two through holes of a seat board, each conductive pin has a lateral contact surface, the two lateral contact surfaces concurrently slidably contact the curved surface so as to diverge the two conductive pins, and the seat board is held by the two diverged conductive pins so as to prevent the seat board from being separated from the capacitor. The friction resistance between the conductive pin and the rotatable structure is decreased due to the sliding contact between the lateral contact surface and the curved surface.