An experimental prototype of in- line,low pulse pulsing continuously variable transmission（ CVT） is designed and manufactured,its basic structure and working principle are introduced in detail. The transmission efficiency of CVT is investigated by experimental method,a transmission efficiency test bench of the CVT is established,and the transmission efficiency experiment of the CVT is carried out. The experiment results show that the power losses of the CVT almost linearly increases with the increasing of the output torque,then increases gradually after a peak and tends to be stable,and decreases later. The transmission efficiency of the CVT and output torque is linear relationship within the allowable range.