In this paper a novel filtering algorithm,called Radar/Infrared(R/IR) converted measurementsfilter Interacting multiple model (R/IRCMF-IMM),is proposed for tracking a maneuvering target usingRadar/Infrared heterogeneous sensors. This filtering algorithmis developed by converting the polar measurementsof Radar and Infrared to Cartesian coordinates, and calculatingthe statistic characteristics of converted measurementerrors before filtering, then applying to the IMMtechnique. Since there are no linearization errors of themeasurement model in the process, the new method hasbetter tracking performance than traditional IMM that usingExtend Kalman filters (EKFIMM). Additionally, thenew method has equal calculation cost with EKFIMM. Finallya simulation example is given and shown that the proposedalgorithm achieves significant improvement in theaccuracy of tracking estimation comparing with the EKFIMM.