Many high entropy alloy systems have been exploited in the past decade and among them AlCrFeCoNi alloy is widely studied. The structural and mechanical properties of AlCrxFeCoNi alloy was studied in this paper for different content of chromium (atomic ratio, x= 0.2 to 2.0 at. %). In this study, ten samples having different chemical composition were prepared from raw materials using RAV equipment, type MRF ABJ 900. The microstructure features, crystallite sizes and microhardness depends on chemical composition of the alloy. The microhardness values for AlCrxFeCoNi (x = 0.2 to 2 at. %) increases from 389.6 to 562.6 HV0.1. The maximum value of microhardness for the high entropy alloy AlCrxFeCoNi (x = 1), has been obtained for 20.55 wt% Cr and has the value 562.6 HV0.1.