Abstract: The spraying field and cutting performance of oils on water (OoW) in the machining of compacted graphite iron (CGI) using cutting tools with hard coatings has been investigated in this paper. Three types of spray nozzles with different structures were used to explore their spray filed, as well as their chip flow during the machining of CGI. Cutting force by using specified spray nozzle and different coated tools were further analyzed under different spray locations. The results showed that, compared to the ordinary cylindrical- and flat-typed spray nozzles, the sharp mouth-typed one had concentrated jet flow, stable and continuous spray low, and no droplets of large size, hence better atomization effect. The ordinary cylindrical- and sharp mouth-typed spray nozzles had the ability to break chips when the spray position of only spraying to the rake face was applied during the machining of CGI. When spraying to the rake and flank faces simultaneous, the chip flow can obtain good flowing orientation, only with the sharp mouth- and flat-typed spray nozzles. Using the sharp mouth-typed spray nozzles, the cutting forces of OoW were 30 to 60 N lower than the cryogenic air cooling and dry cutting. The OoW with only spraying to the rake face has the lowest cutting force. Moreover, the cutting tools with hard coatings should be matched with the spray position of OoW in order to obtain the lowest cutting force.