在Born近似条件下,文中讨论了地震反射式弹性波三参数（密度和二个接梅参数）的衍射CT问题,给出了地表反射条件下的散射场积分表达式,和在单一频率的情况下,充分利用各类波型所包含的信息,从散射波场中分离出4种不同类型的散射波的数学表达式。最后,推导了多参数在变换域内解耦的衍射CT反传播公式。本文仅作公式推导,理论模型的数值计算将另文发表。 Under the condition of Born approximation, the diffraction CT problems of three parameters (density and two plume parameters) of seismic reflection elastic wave are discussed in this paper. The integral expression of scattering field under the surface reflection condition is given, and in the case of single frequency , Make full use of the information contained in all kinds of waveforms to separate the mathematical expression of four different types of scattered waves from the scattered wave field. Finally, the anti-propagation formula of multi-parameter decoupled diffraction CT in the transform domain is deduced. This article is only derived from the formula, the theoretical model of the numerical calculation will be published separately.