Abstract: Laboratory experiment and parameters of nitrogen- foam profile control technique are conducted to solve the steam breakthrough in thermal recovery well for dense oil in Henan oil field.Through the static performance evaluation and consecutive single and dual string displacement experi- ment,the optimal mass fraction of foaming agent and the op- timal gas liquid ratio are obtained:the mass fraction of foa- ming agent as 0.5%;the deduced optimal ratio of nitrogen and steam production under the ground condition as about 40 :1;and the injection amount in the foam profile control see- tion of individual well of steam breakthrough as about 0. 1PV.In 2007,through experiments of nitrogen- foam pro- file control in 7 wells,a success ratio of measure as 85.7 is acquired and the steam injection pressure of individual well after measure increased by 0.6MPa,which effectively block the steam breakthrough channel of thermal recovery well.