In view of the different types of jamming faced by satellite communication, frequency-shift keying (FSK) modulated communication signal was taken as the research object, and the relationship between the bit error rate and the signal-to-jamming ratio was mainly studied under the nine countermeasure conditions of jamming, such as single-tone, multi-tone, narrowband, multi-tone narrowband, noise amplitude modulation, noise frequency modulation, noise phase modulation, linear frequency modulation jamming, and pulse jamming. The deterioration degree of the FSK modulated communication system with different types of jamming in the case of different frequency biases and signal-to-jamming ratios was obtained through simulation, and the optimal jamming type was obtained. At the same time, the maximum signal-to-jamming ratio required to block communication (with a bit error rate greater than 10⁻²) under different frequency biases and different types of jamming was obtained. When the signal-to-jamming ratio was less than 0 dB, the single-tone jamming and noise frequency modulation jamming caused more serious system deterioration. When the signal-to-jamming ratio was greater than 0 dB, the noise frequency modulation jamming, the multi-tone narrowband jamming, and the pulse jamming exhibited better jamming effect. In the case of different frequency biases, the pulse jamming required the minimum power to block communication.