The incoherent sound field obtained by scanning measurement cannot be used directly for nearfield acoustic holography to reconstruct the sound field. And therefore, the incoherent sound field needs to be decomposed into fully coherent partial fields. In previous methods, the pressure is used as reference to obtain the partial fields. In this paper, the pressure gradient is used as the reference for the partial field decomposition. Because the pressure gradient decays faster than the pressure, the interaction of the pressure gradient between the incoherent sources is weaker than that of the pressure, which may improve the effect of the partial field decomposition. A numerical simulation and an experiment are conducted to test the feasibility of the method. And it is shown that the partial field decomposition method based on pressure gradient reference is robust and the decomposed results are better than those based on pressure references.