A shift system related to an improved continuously variable transmission (CVT) may include a power output assembly, a power input assembly, a collar assembly, and a connecting assembly to connect the power output assembly and power input assembly. The shift system is advantageous because it employs only gears and hydraulics for the transmission of power, which can be used in any torque scenario, from low-torque to heavy-duty scenarios such as large passenger automobiles, large trucks and heavy-duty machinery. Furthermore, there is no need to use additional energy to keep the transmission tight enough to engage and to prevent any slipping, and the overall efficiency of power transmission would be increased.