The optimal multiple linear constraint minimal variance (LCMV) beamformer is presented under multiple desired signals case. The theoretical solutions of the optimal weighted vector and maximum signal-to-interference-plus-noise-ratio (SINR) are derived by using variable substitution method. Simulation results show that the algorithm is superior to the traditional LCMV approach in the SINR, computational load and applicability. The algorithm can be applied in the area of radar tracking of low-angle targets and polarization radar signal processing.