The unsupported structure obtained by topology optimization under the condition of deterministic symmetric load can not meet the actual engineering requirements. The uncertainty of load direction was incorporated into the structural optimization design. And its influence on the avoidance of unsupported structure was analyzed. This paper uses interval variables to represent the uncertainty of the load direction, uses Taylor formula to solve the sensitivity under the most sensitive loading condition, and uses SIMP model and MMA algorithm to design the robustness of continuum structure. The optimization results show that the structural optimization considering the uncertainty of load direction can effectively avoid unsupported structures. Under uncertain symmetric loading conditions, the structural compliance shows an upward trend with the increase of the disturbance range. And the structure shows symmetry. Under uncertain asymmetric loading conditions, the influence of asymmetric loading on structural compliance is significant, and the structural asymmetry characteristics tend to be more obvious with the increase in the variability of disturbance ranges.