A series of bonded magnets of (Nd,Pr)10.5(Fe,Co)83.5-xMxB6 (M=Zr, Nb, Ti) alloys were prepared by the melt-spun method. The effects of Zr, Nb and Ti element on the microstructure and magnetic properties of alloys have been investigated. The grains of (Nd,Pr)10.5(Fe,Co)83.5B6 with suitable addition of Zr, Nb, or Ti element are finer and more homogeneous. The average grain size is about 50~70 nm. Due to the combined effect of grains refining and pinning to magnetic domain wall of non-magnetic phases, the demagnetization curve rectangularity is improved notably, and the value of Hk/Hcj and other magnetic properties are also greatly increased for the bonded magnets with Zr, Nb, and Ti element addition. Compared with Nb and Ti, Zr has the best effect on refining the grains and increasing magnetic property. For the (Nd,Pr)10.5(Fe,Co)82.5Zr1B6 alloy with 1% Zr, the grains are ~60 nm and homogeneous, the demagnetization curve rectangularity is the best, the Hk/Hcj reaches to 39.9%, and Br, Hcj, and (BH)m are 0.675 T, 616 kA/m and 77 kJ/m3, respectively.