This paper proposes an adaptive rotation-based enhancement method for direction-of-arrival （DoA） estimation of co-frequency multiple emitters using a uniform linear array （ULA）. Addressing the limited estimation accuracy of traditional fixed arrays in multi-source scenarios， a dynamic rotation mechanism is introduced to establish an analytical relationship between the rotation angle and the Cramer-Rao bound （CRB）， leading to the derivation of a closed-form solution for the optimal rotation angle. The trace of the CRB is employed as the loss function， representing the theoretically achievable lower bound of the mean squared error. By minimizing the CRB， the system observability is enhanced， thereby improving the estimation accuracy of DoA algorithms. Given that the CRB in multi-source scenarios is a correlated matrix， a simplified diagonal form of the CRB is derived under the condition of a sufficiently large number of snapshots. This simplified diagonal CRB is utilized for optimization， significantly reducing computational complexity. To achieve high-precision DoA estimation， prior information about the signal incident angles is first obtained using a fast algorithm. This prior is derived from covariance matrix computations after the array receives and samples signals from multiple radiation sources. Subsequently， the rotation angle that minimizes the loss function is determined and adopted as the optimal array orientation. After adjusting the array to this angle， the DoA estimation algorithm is reapplied at the same position to obtain the final DoA results. The proposed method maintains high estimation accuracy under multi-source conditions and effectively enhances overall direction estimation performance. Simulation results demonstrate that the method significantly reduces the CRB， improves localization accuracy， and enhances the resolution of spectral search-based algorithms.