The double-perovskite Sr₂FeMoO₆ compound have been prepared at 1 373K by sol-gel method.The sample's microcosmic shapes,phase formation and Magnetic properties were systematically investigated by means of X-ray diffractometer,atomic force microscope,the thermogravimetric-DSC analysis and Physical Property Measurement System(PPMS).The results indicated that the prepared sample is pure phase,the sample particle size uniformity,grain boundary clear and higher quality.And if the sintering temperature is higher than 1 023K,the sample will become phase.When external field is 30 000Oe and the temperature of the sample for the 10K and 300K,magnetoresistance is 16.25% and 5% respectively.