ＣＥＬＰ以其高质量的合成语音及优良的抗噪声和多次转接性能，在移动通信，保密电话和语音中继等中低速率上获得了广泛应用。由于ＣＥＬＰ的运算量庞大，减少其运算量一直是研究的热点。自适应码本是多数ＣＥＬＰ方案中的重要环节。本文对自适应码本的快速搜索算法进行了研究，并在端点递归法的基础上提出了一种双层搜索法。实验表明，此方法既保持了复原语音的高质量的特点，又明显地降低了运算量。 CELP is widely used at medium and low rates, such as mobile communications, secure phones and voice trunks, for its high quality synthesized speech and excellent noise immunity and multiple transfer performance. Due to the huge amount of computation of CELP, reducing its computational complexity has been a hot spot of research. Adaptive codebooks are an important part of most CELP scenarios. In this paper, the fast search algorithm of adaptive codebook is studied, and based on the endpoint recursion method, a double-layer search method is proposed. Experiments show that this method not only maintains the high quality of reconstructed speech, but also significantly reduces the computational complexity.