The systems RbF-GaF3 and CsF-GaF3 were re-investigated by DTA and XRD method. In the system RbF-GaF3, with eutectic El at 750 degreesC in the location of 8.5 mol% GaF3 and E-2 at 749 degreesC in the location of 43.0 mol% GaF3, three compounds Rb3GaF6, RbGaF4 and RbF . 2GaF(3) were identified and indexed by XRD. The indexed result of alpha -Rb3GaF6 could not be successfully obtained, beta -Rb3GaF6 is tetragonal, a=6.324+/-0.004, c=8.860+/-0.003 Angstrom. RbGaF4 is orthorhombic, a=9.821+/-0.006, b=9.517+/-0.005, c=8.060+/-0.006 Angstrom; RbF . 2GaF(3) is also orthorhombic, a=9.459+/-0.005, b = 9.336 +/-0.005, c = 7.685 +/- 0.005 Angstrom. In the system CsF-GaF3, with eutectic E-1 at 664 degreesC in the location of 7.5 mol% GaF3 and E2 at 675 degreesC in the position of 44.0 mol% GaF3, two compounds were confirmed, alpha -Cs3GaF6 is orthorhombic with a = 10.62 +/- 0.02, b = 9.959 +/- 0.006 and c = 5.607 +/-0.005 Angstrom: beta -Cs3GaF6 is also orthorhombic, a = 10.356 +/- 0.003, b = 8.280 +/- 0.003, c = 7.621 +/- 0.005 Angstrom; gamma -Cs3GaF6 is tetragonal, a = 6.833 +/- 0.003, c = 9.869 +/- 0.002 Angstrom; CsGaF4 is orthorhombic, a = 8.571 +/-0.007, b = 7.575 +/- 0.007 and c = 6.981 +/- 0.006 Angstrom.