The two-port circuit theory is introduced to a contactless power transfer(CPT)system

by means of which an LCL type CPT system is modeled and analyzed. After that

the relationship between the input and output voltage is found. At the same time

the new model of the coupling mechanism is given

which makes the analysis very simple. Based on this

a new parameter configuration method of the whole system is given

and the output voltage

power and efficiency characteristics are analyzed. In order to prove the superiority of this method

the output power formula of an SS type CPT system is deduced and compared. The results show that the proposed method has a much higher output voltage and power as proved by simulation and experimental results.This work is supported by National High Technology Research and Development Program of China(863 Program)(No. 2015AA016201)and National Natural Science Foundation of China(No. 51277192).