High B (s) Fe82.5Si3B13P0.5C0.2Cu0.8 alloys with high impurity tolerance were successfully developed and prepared into ribbons with fully amorphous and uniform nanocrystalline microstructure. By comparing samples made with industrial grade and pure raw materials, it is found that the impurities in the commonly used industrial grade raw materials mainly affect the amorphous forming ability and amorphous structure of the as-spun ribbons. The effects of impurities on crystallization behaviors and magnetic properties can be inhibited in the amorphous ribbon production process for the alloys with a high impurity tolerance. The Fe82.5Si3B13P0.5C0.2Cu0.8 nanocrystalline alloy ribbons prepared with industrial grade raw materials exhibit excellent magnetic properties, containing high B (s) over 1.79 T, low H (c) of 9.5 A/m and maximum permeability (mu (m)) of 4 x 10(4), which are similar to the samples made with pure raw materials with unacceptable high cost. Combining the low cost of raw materials, good manufacturability and excellent magnetic properties, the present Fe82.5Si3B13P0.5C0.2Cu0.8 alloy will become a promising candidate for mass production and also provide a good reference for future development of high B (s) nanocrystalline alloys.