Abstract: In order to accelerate the expansion of steam chamber and to reduce the impact of interlayers during SAGD development for heterogeneous heavy oil reservoirs, a steam injection method with fishbone horizontal well is put forward. Taking Wellblock A of Fengcheng oilfield as an example, main factors influencing production effects of SAGD technology with fishbone steam-injection horizontal well are analyzed and branch shapes and key injection-production parameters are optimized by using numerical simulation technique. The study results show that horizontal and vertical displacements of branches are positively correlated with production effects of well groups, and the production effect of staggered branch distribution is better than those of symmetry and same-side branch distributions. When interlayers exist above fishbone steam-injection horizontal wells, the optimum production effect can be gained when the branches go across the interlayers. The actual application shows that both initial daily oil production and oil/ steam ratio of the fishbone steam-injection horizontal wells are higher than those of horizontal wells without a branch under the same conditions. The production method has certain advantages and can be guidance for similar reservoir development