Conventional beamforming (CBF) is an important processing step in underwater array signal processing. Previous researches have shown that the sound field structure as manifested by amplitude nonhomogeneity and wave-front corruga-tion can reduce the array gain of CBF. The acoustic environment of the continental shelf slope area is very complex. For an underwater acoustic array in this area, the amplitude and phase of the received signals will be distortional seriously. Recently, the acoustic field correlation has been the focus of research on the array gain relations with the underwater acoustic filed. However, the attenuation of acoustic field correlation is not the only factor that induces the array gain to decline, and the analyses of the array gain in the shallow water based on normal-mode model are not applicable to the continental slope area. In this paper, the array gain relations with the structure of acoustic field in continental slop area are investigated based on the theory of underwater acoustic signal propagation. The effects of acoustic field on the signal and noise gains are considered respectively. The analytic expressions of the array gain of CBF in an isotropic noise field are derived from the primal definition of array gain, which indicates that acoustic field correlation and transmission loss in continental slope are the intrinsic factors that affect the array gain of CBF. A horizontal uniform linear array (ULA) with a wide aperture receiving signals from a source in the deep water region is considered in the upslope propagation condition. The RAM program is utilized in the numerical simulations to generate the sound field of this specific envi-ronment with given parameters. The array gains, the ATLs and the horizontal longitudinal correlation coefficients of the acoustic field corresponding to three different locations are compared. Conclusions can be drawn as follows. 1) The array gain of CBF is determined by acoustic field correlation and the acoustic average transmission loss (ATL), and its maximum is less than 10 lg M as the signal waveform distortion. 2) when the ATLs corresponding to hydrophones at two different receiving locations are similar, the correlation of acoustic filed is higher, and the array gain of CBF is larger. 3) When the ATLs corresponding to hydrophones at two different receiving locations are greatly different, the relation between the array gain of CBF and the acoustic filed correlation is no longer positive. The simulation results verify the array gain of CBF relations with the acoustic filed correlation and the transmission loss in the continental slope area.%常规波束形成是水下阵列信号处理中最基本的处理环节。陆架斜坡海域特殊地形所带来的水下声场变化会影响阵增益。以往的研究中，只关注声场相关性对阵增益的影响。本文基于水声信号传播理论，研究常规波束形成阵增益与陆架斜坡海域水下声场之间的关系，证明声场相关性和传播损失是影响阵增益的内在因素，并推导了各向同性噪声场中常规波束形成阵增益与两者之间的关系式。结果表明：1)常规波束形成阵增益由声场相关性和声传播损失共同决定，其最大值不超过10 lg M；2)当两个不同接收位置的传播损失相似时，基阵各阵元间的声场相关性越高，阵增益越大；3)当两个不同接收位置的传播损失相差较大时，阵增益与声场相关性不再是正相关关系。利用RAM声场软件，在陆架斜坡海域上坡波导环境中，对水平阵常规波束形成阵增益与声场相关性和传播损失的关系进行仿真验证。
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