Objective To observe the ultrastructural chang of necroptosis during renal development in mice. Methods Renal necroptosis of three mice aged at embryonic days (E)12,14,16,18 was examined by using electron microscopy. Results There was necroptosis, or programmed necrosis, in the developmental embryonic kidney tissue. EM observations demonstrated that cell necroptosis was similar to cytoplasm appearances of cell necrosis and nuclei of cell apoptosis. Those appearances were swelling cytoplasm with disrupted plasma membrane, and nuclei with shrinkage and margination of chromatin. Conclusion Programmed cell death is composed of necroptosis, oncosis and apoptosis during renal development and apoptosis is more principal.