The invention discloses a comprehensive transmission device of a light all-territory vehicle. A cavity is formed after a left box and a right box are combined. The cavity is internally provided with a torque extraction gear assembly, a power cut-off assembly, a straight driving gear assembly and a stepless convergence differential assembly. A sliding pawl and a shifting fork in the power cut-off assembly are fixedly connected and connected to a torque extraction intermediate shaft through a key. A straight driving input gear of a speed changing gear assembly is normally engaged with a gear on a straight driving intermediate gear shaft. The straight driving intermediate gear shaft is further fixedly sleeved with a straight driving intermediate gear normally engaged with a gear on an input gear shaft. The two ends of the input gear shaft are coaxially fixed with a gear ring on a left planet row combination and a gear ring on a right planet row combination through bolts respectively. All the components are integrated, integrity is high, the occupied space is small, and the whole vehicle arrangement is facilitated. Meanwhile, the comprehensive transmission device is provided with two output ends including a first output gear shaft and a second output gear shaft, power output is convenient, and power cutting off can be achieved through electromagnets.