In order to analyze the characteristic of current in-situ stress field of the Fengshan formation, using the strike of drilling inducing fracture and direction of hole-wall collapsing, the direction of current in-situ stress of the Fengshan formation was judged, and the value of current stress is calculated by logging data and empirical formula. Based on above, taking ground stress results of key wells as constraint condition, horizontal distribution of current in-situ stress field was analyzed by numerical simulation with confirming rock mechanical parameters and building finite element model. Meanwhile, the impact on fracture efficacy of current in-situ stress field was analyzed. The result demonstrates that, the maximal horizontal principal stress is 90.6-181 MPa, and the direction is close to NEESWW;the minimal horizontal principal stress is 61.9-110 MPa, and the direction is close to NNW-SSE. Low value of current stress appears in faults. The value of current stress in arch core distributes stably. There are two stress gradient zones in anticlinal flanks. High value of current stress appears in the low-lying areas near the east and west sides. According to the simulation results, the impact of stress on the fracture efficacy was analyzed. Effective fracture strike of the Fengshan formation is close to NEE-SWW. The arch core is the best area for effective fracture development, followed by the anticlinal flanks and the low-lying areas.