Abstract: To solve the problem of having high sidelobe level for the direct data domain(DDD) beamforming,a weighted DDD beamforming algorithm is proposed based on constraint optimization.To obtain the suppressive effect of sidelobe,the new algorithm sets a proper mainlobe beamwidth according to the mainlobe direction or the pre-forming beampattern direction,and restricts the highest sidelobe level to a certain value.Two forms of constraint optimization are analyzed.One form is fixing sidelobe level while changing mainlobe beamwidth,the other is fixing mainlobe beamwidth while changing sidelobe level.It is shown by simulation that the weighted DDD beamforming algorithm performs well,and the sidelobe level can satisfy the design requirements when the presetting mainlobe beamwidth is slightly greater than the original DDD beampattern mainlobe beamwidth.