In order to solve the existing problems of dual-channel fiber optic r otary joint (FORJ),a novel dual-channel FORJ based on lens group system is pres ented in this paper.The central channel of the dual-channel FORJ consists of two fiber collimators,where the optical signals can be transmitted by means of direct coupling;the optical signals in the off-axis channel can be continuou sly transmitted by the circular symmetry of the lens group system.It is important to note that the design of the off-axis chan nel is the key problem to establish the dual-channel FORJ.The optical systems of this FORJ using the optical collima tor and the large- core fiber as receiver are analyzed by ray tracing based on the geometric optics law,respectively.In addition,the performance of the dual-channel FORJ is investigated.The experimental results s how that the insertion loss of the central channel is less than 1.84dB,and the loss due to t he rotation is about 0.59dB;the maximum insertion loss of off-axis channel is 2.40dB and the loss due to the r otation is less than 0.76dB.The return losses of central channel and off-axis channel are 40dB and 45dB,respectively .The performance can meet the requirement of this kind of FORJ.