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A new kinetic model for multiphase flow was presented under the framework of the discrete Boltzmann method(DBM).Significantly different from the previous DBM,a bottom-up approach was adopted in this model.The effects of molecular size and repulsion potential were described by the Enskog collision model;the attraction potential was obtained through the mean-field approximation method.The molecular interactions,which result in the non-ideal equation of state and surface tension,were directly introduced as an external force term.Several typical benchmark problems,including Couette flow,two-phase coexistence curve,the Laplace law,phase separation,and the collision of two droplets,were simulated to verify the model.Especially,for two types of droplet collisions,the strengths of two non-equilibrium effects,-D*2and-D*3,defined through the second and third order non-conserved kinetic moments of(f-feq),are comparatively investigated,where f(feq)is the(equilibrium)distribution function.It is interesting to find that during the collision process,D*2 is always significantly larger than-D*3,-D*2can be used to identify the different stages of the collision process and to distinguish different types of collisions.The modeling method can be directly extended to a higher-order model for the case where the non-equilibrium effect is strong,and the linear constitutive law of viscous stress is no longer valid.