The northern transitional zone of Area S has the characteristics of high water cut, low oil recovery rate, rapid production decline, rapid rise of comprehensive water cut and poor development effect in oilfield development. In order to improve the development effect of the transition zone, the test of steam flooding infill adjustment was carried out in three or four zones in the northern transition zone. In this paper, a fine structure model and a fine reservoir model were established for the test area, historical fitting and precision analysis were made for the geological reserves and production, and set adjustment was made for the test area. Therefore, the change rule of the index before and after well pattern infilling and the effect evaluation can also effectively solve the problem of low reserve utilization caused by poor reservoir development and poor physical property of crude oil in the transitional zone. The research in this paper can also effectively guide the adjustment of measures and the preparation of comprehensive schemes.