As a crucial component of weather systems, 3D cloud simulation plays a significant role in various fields such as military and aviation. However, the current mainstream Bounding Volume Hierarchy (BVH) algorithm exhibits inefficient rendering performance when dealing with non-uniform and large-volume clouds. To address this issue, a cloud rendering method based on optimized BVH algorithm is proposed. The data points from the WRF grid are used as cloud primitives, and a Z-order Hilbert curve is employed for spatial sorting. The BVH algorithm based on the Surface Area Heuristic (SAH) is optimized by locally optimizing the cloud primitive density, aiming to enhance computational efficiency. To tackle the data access overhead of overlapping BVH nodes, a novel storage structure called Overlapping Node Sets (ONS) is introduced, which reduces the time complexity. The optimized BVH algorithm reduces unnecessary intersection tests between rays and triangle surfaces, and resolves issues related to invalid boundary volume overlaps. Simulation experiments demonstrate that the proposed method achieves a 15.6% improvement in SAH cost compared to similar state-of-the-art algorithms, a 10% improvement in EPO, and a reduction of over 100% in construction time. The computational efficiency of the optimized BVH algorithm outperforms similar algorithms in any WRF cloud scenario, indicating its capability for rapid rendering of WRF cloud products.