Hole doped double perovskite compounds (Sr, Na)2FeMoO6 with the Na content of x = 0, 0.02, 0.03, 0.07 and 0.17 have been synthesized by sol-gel method. Effects of hole doping on the crystal structure and magnetic properties of Sr2FeMoO6 have been investigated. XRD pattern indicates that all the samples are of single phase and belong to the space group I4/m. The degree of cation ordering in the Na-doped Sr2FeMoO6 compounds shows a non-monotonic variation with the doping level. The saturation magnetization of the compound increases with x for x<0.17. Similar to the electron doped Sr2FeMoO6, provided that the doped hole enters selectively the spin-down band, the variation of the saturation magnetization can be explained in light of the ferrimagnetic model (FIM).