Due to the low transmitting power and large transmission loss, the satellite signal reaching the GNSS receiver is extremely weak, and easy to be interfered. In order to deal with the threat of electromagnetic interference, taking measures at both the system and user level would be a good choice. A model for analyzing the interference suppression capability of anti-jamming receiver with null-steering antenna was established, and the improvement effect of signal power enhancement on the interference suppression performance was quantitatively analyzed. Results show that, the interference mitigation capability of the receiver can be improved by 3～4 dB per 10 dB signal power enhancement. However, from the perspective of improving the receiver′s reception performance(carrier to noise ratio, ranging and positioning accuracy, etc.) under non limiting conditions, when the signal power is increased by 15～20 dB, the reception performance is optimal. The research result can guide the optimization of the signal power enhancement and anti-jamming design of receivers.