Abstract: The minimum variance distortionless response (MVDR) algorithm is affected by the desired signal (DS) power even if all signals are uncorrelated with each other when the received array data contains the DS. Under the assumption that all signals are independent with each other, this paper analyses the influence of the DS power on the output DS power and the output power of the interference plus noise at first. Then, it analyses the change of the output signal-to-interference-plus-noise ratio (SINR) and its convergence rate with the impact of the DS power. The analysis shows that the output SINR increases with greater DS power within a certain range. However, for the DS power large enough, the ability of the interference suppression would be weaken, which results in an unchanged output SINR no whatever how large the DS power. Moreover, the output SINR suffers from slower convergence rate for larger DS power. The simulations validate the effectiveness of the analysis.