Certain irradiance profile of laser output is needed to increase the entire efficiency of laser system. Beam shaping with adaptive optics based on stochastic parallel gradient descent (SPGD) algorithm is developing rapidly because of its outstanding applicability, however, shaping effect of this method largely depends on the target beam size. A new method of far field irradiance profile control is presented. The input beam is shaped in the near field with SPGD algorithm, and then imaged by a 4f system. The effect of far field irradiance profile control is studied for the input beams with and without wavefront aberration. Size control of the far field irradiance profile is analyzed. The result reveals that the new system could realize beam shaping whether the input beam has wavefront aberration or not. And it could realize size control of the far field irradiance profile. The new system has better applicability and utility than traditional ones.