The transport of intensity equation (TIE) is solved to recover the phase inf ormation through the combination of optics and calculation with the method of phase retrieval based on the intens ity measurement.It is proved to be a feasible way to obtain phase information theoretically and experimentally.The s ensitivity and resolution problems because of the interferometry techniques are avoided.However,the method is derived under the assumption of coherent illumination.It is difficult to expand it to the partially coherent opt ical field.A partially coherent optical field at any point in the space experiences statistical fluctuations over time.To fully char acterize this field,correlations between pairs of points need to be used.Combining the phase modulation of lens and characteristics of partially coherent field,a new phase retrieval method under partially coherent illuminati on based on the lens imaging model is deduced.Finally,the phase retrieval results are given under uniform and non -uniform illumination. Experimental results verify that this new phase retrieval method is reasonable a nd correct.The application of traditional phase retrieval algorithm on transport of intensity equation is exte nded.