In order to remedy the situation of one sending end in the wireless power transmission system having to supply power to systems with multiple loads at the same time

research is made on the mechanism of mutual transformation between such systems' power and efficiency. First thing is to define the key parameters about generalized mismatch factor

the generalized coupling factor

load factor and impedance ratio of the initial and secondary system. Utilizing these parameters

the circuit model of wireless power transmission system is developed

and the basic characteristic formula of the voltage gain

output power gain and transmit efficiency are deduced. Secondly

a novel method is presented to show how these parameters influence voltage gain

output power gain and transmission efficiency of multi-load wireless power transfer systems. In the end

an experimental circuit is designed which shows the correctness of the proposed method and its results as well as suggestions for design of multi-load wireless power transmission systems via magnetic coupling resonance. This work is supported by National Basic Research Program of China(973 Program)(No. 2014CB049405).