Abstract: A GLONASS receiver front end structure and its frequency synthesizer part are given based on the GLONASS frequency plan. The synthesizer is realized with integrated PLL frequency synthesizer. It is easy to be constructed and also has the advantage of good stability. The design details of the frequency synthesizer is given. The inherent synthesizing error is analyzed and the method of eliminating it is discussed. The theoretical performance of the synthesizer is provided. The experiments show that the synthesizer has good stability and high precision. It meets the requirements and can be applied to the GLONASS receiver.