The existence of lens in homogeneous earth dams has great influence on the original seepage field. The effects of lens on the phreatic line and seepage flow of seepage field in the dam body was studied in order to provide technical support for the design and practical engineering construction of homogeneous earth dams, so as to effectively improve dam safety. Taking a homogeneous earth dam with impervious foundation as the research object, by changing four characteristic parameters (permeability coefficient, relative position, area and shape) of the lens, we calculated the phreatic line and seepage flow of the dam body respectively using the two direction stable and unstable seepage calculation program DQB. The results showed that the permeability coefficient, the relative position and the area of the lens had a significant influence on the phreatic line and seepage flow of the dam body, whereas the shape of the lens had little influence on the seepage field. Therefore, setting appropriate values for the characteristic parameters of the lens can change the seepage field of the dam body, which in turn will improve the dam safety or water storage capacity in practical dam construction projects.