While sharing and processing digital data, many problems arise due to huge evolution in technology. The first and front most important issue is security. In order to conquer this problem a technique known as Digital water marking is applied to digital data while undergoing sharing and processing. In the recent years many researchers have proposed several methods. The selection of optimal scaling factor is a main problem in the watermarking. The proposed technique is a Optimal Alpha based Curvelet and SVD (OACSVD), called the Cuckoo Search (CS) which is used to find the optimal scaling factor for grey image watermarking in CWT-SVD transform domain. The OACSVD method handles secret sharing to accomplish more security of watermark. The proposed technique used many attacks to explore the robustness and various results are obtained. OACSVD method shown PSNR and NCC values as 44.13% and 99.29% respectively.