Structure and magnetic properties of the (Nd1-xErx)3Fe25Cr40 (x=0—10) compounds have been investigated by means of x -ray diffraction and magnetic measurements. It is found that the compounds with x =0—08 crystallize in Nd3(Fe,Ti)29-type structure, A 2/m space grou p, but those with 082Ni17-type structure, P63/mmc space group. Both the Curie tem perat ure Tc and the saturation magnetization Ms of (Nd1 -xErx)3Fe25Cr40 de crease monotonically with increasing Er content. The easy magne tization direction (EMD) of the Nd3Fe25Cr40 compound is close to the ［040］ direction at room temperature, but makes a tilted angle with the ba sal plane of 1∶5 structure. With increasing Er content the EMD changes to much close to the [402] direction and the tilted angle increases. AC susceptibility m easurement indicates the appearance of a spin reorientation at low temperatures for the compounds with x=0—04 and x=10, and the spin reorientation temperature Tsr increases monotonically as the Er content increas es fo r the compounds with x=0—04 First-order magnetization process (FOMP) is observed in the compounds with 0≤x≤08 and the critical field Bc rof the FOMP decreases with increasing Er content from 66T for x=0 to 20T for x=07