The invention discloses a twin engined parallel operation clutch ship gear box with PTO, wherein a port input shaft assembly and a starboard input shaft assembly are supported in a box body (1) on both sides of an output shaft (2) through bearings respectively; a first input shaft(7) and a second output shaft(8) are connected through a clutch(9) to form the port input shaft assembly; a third input shaft(10) and a fourth output shaft(11) are connected through the clutch(9) to form the starboard input shaft assembly; and the second output shaft(8) of the port input shaft assembly and the fourth output shaft(11) of the starboard input shaft assembly are sleeved with driving gears(12), and the two driving gears(12) are meshed with corresponding driven gears(13) on the output shaft(2) simultaneously. The gear box has the advantages of saving space, increasing article-carrying space, lowering cost, using different clutch operating modes under different work conditions, being simultaneouslyswitched between opening and closing to generate power and further greatly saving fuel oil cost of a main machine.