According to 13 ICCC the main tendency of development of science and technology of cement and concrete are decrease of CO2 at cement manufacture, production of low clinker contained cement, low energy consumer cement, etc.For this aim, Slag Portland Cement is namely such binding material that is low energy consumed cement.At its production energy consumer is twice lower than at Portland cement manufacture.Nevertheless,enterprises of building industry use SPC reluctance as its hydration and hardening is lower than Portland cement.This paper deals with the study of influence of the different factors on hydration and hardening of SPC.It is shown the influence of mineralogical composition, crystallize materials (crents: SAC, CFC, etc), fineness of cement, technic milling on SPC properties.The aim of this investigation was to fix parameters of blast furnace slag cement grinding.It is shown that Portland cement clinker and slag particle distribution is differed as they grindability are differ each other.To increase of slag fineness and strength cement paste it is need cement milling in two-stage method.Cement activated by special mill is useful too.