We report spin polarization P of Ru2-xFexCrSi Heusler alloys by the Andreev reflection technique. Ru2-xFexCrSi with L2(1)-type structure and saturation magnetic moment of 2 mu(B) per formula unit is theoretically predicted to be half-metals in the wide range of the composition x. We had clarified that the experimental results of saturation magnetic moment in Fe-rich compounds had coincided with the theoretical prediction. Therefore, we have measured the differential conductance of Ru2-xFexCrSi/Pb planar-type junctions. The P value of Ru2-xFexCrSi was determined by fitting the differential conductance with the modified Blonder-Tinkham-Klapwijk theory. We have found that the behavior of P for Ru2-xFexCrSi was independent of the composition x in the Fe-rich region: P=0.53 for both of x=1.5 and 1.7. The spin polarization is the similar value to Co-based Heusler alloys. (C) 2010 Elsevier Ltd. All rights reserved.