The invention discloses a hybrid power coupling mechanism. An output shaft of an engine (1) is fixedly sleeved with a first sun wheel (2), the first sun wheel (2) is meshed with a first outer ring (5) through first planet gears (3), all the first planet gears (3) are arranged on one end face of a planet carrier (4), second planet gears (7) are arranged on the other end face of the planet carrier (4), and all the second planet gears (7) are meshed with a second outer ring (6) and a second sun wheel (8); a big gear wheel (9) is coaxially fixed to the second sun wheel (8) and meshed with a pinion (11), and the pinion (11) is arranged on a main shaft of an ISG motor (10) in a sleeved mode. According to the hybrid power coupling mechanism, the optimum driving form under different working conditions can be achieved, power performance demands can be met, and fuel economy can be effectively improved; the hybrid power coupling mechanism has the advantages of being simple and compact in structure, small in size, easy to assemble, low in production cost, convenient to control, little in power loss, good in reliability, and the like.