Abstract: Facing the realities of stream severe overlapping and channeling in late cyclic steam injection production in Le’an heavy oilfield, by the nitrogen characters of diluting and decreasing viscosity and increasing flexible steam flooding energy, the study researches and evaluates nitrogen gas and nitrogen with former in lab, selects the suitable high temperature former. Based on the reasonable steam injection parameters, the restudy works on the tests between nitrogen gas injection and nitrogen former injection on site. This deals with the problems of stream overlapping and channeling caused by different densities between steam and oil. Also it deals with the problem of bottom water coning in burial hill reservoirs, and effectively reduces the non-equivalent producing conflicts between formation level and vertical. It offers the good experience and evidence to the following late reservoir development.