By considering the inhomogeneities of media, a generalized variable-coefficient Kadomtsev-Petviashvili (vc-KP) equation is investigated, which can be used to describe many nonlinear phenomena in fluid dynamics and plasma physics. In this paper, we systematically investigate complete integrability of the generalized vc-KP equation under a integrable constraint condition. With the aid of a generalized Bells polynomials, its bilinear formulism, bilinear Bäcklund transformations, Lax pairs and Darboux covariant Lax pairs are succinctly constructed, which can be reduced to the ones of several integrable equations such as KdV, cylindrical KdV, KP, cylindrical KP, generalized cylindrical KP, non-isospectral KP equations etc. Moreover, the infinite conservation laws of the equation are found by using its Lax equations. All conserved densities and fluxes are expressed in the form of accurate recursive formulas. Furthermore, an extra auxiliary variable is introduced to get the bilinear formulism, based on which, the soliton solutions and Riemann theta function periodic wave solutions are presented. And the influence of inhomogeneity coefficients on solitonic structures and interaction properties are discussed for physical interest and possible applications by some graphic analysis. Finally, a limiting procedure is presented to analyze in detail, asymptotic behavior of the periodic waves, and the relations between the periodic wave solutions and soliton solutions. form, Lax pairs, infinite conservation laws, infinite symmetries, Hamiltonian structure, Painlevé test and bilinear Bäcklund transformation that can characterize integrability of nonlinear equations. Although there have been many methods proposed to deal with the NLEEs, e.g., inverse scattering transformation [1], Darboux transformation [2], Bäcklund transformation(BT) [3], Hirota method [4] and so on. By using the bilinear form for a given NLEE, one can not only construct its multisoliton solutions, but also derive the bilinear BT, and some other properties [4]-[7]. Unfortunately, one of the key steps of this method is to replace the given NLEE by some more tractable bilinear equations for new Hirota's variables. There is no general rule to find the transformations, nor for choice or application of some essential formulas (such as exchange formulas). During the early 1930s, Bell proposed the classical Bell polynomials, which are specified by a generating function and exhibiting some important properties [8]. Since then the Bell polynomials have been exploited in combinatorics, statistics, and other fields [11]-[13]. However, in recent years Lambert and co-workers have proposed an alternative procedure based on the use of the Bell polynomials to obtain parameter families of bilinear Bäcklund transformation and lax pairs for soliton equations in a lucid and systematic way [8]-[10]. The Bell polynomials are found to play an important role in the characterization of integrability of a nonlinear equation.Recently, there has been growing interest in studying the variab...