Multiphase flow analysis using the finite element method with tetrahedral elements is investigated. For the conservative Cahn-Hilliard equation used in the multi-phase-field model [1], a bubble function element [2] is proposed that takes into account an implicit method in the time direction and stabilization in the spatial direction. This simulation employs distributed memory parallel computing based on domain decomposition. In this paper, parameter identification of the physical property values that appear in the Cahn-Hilliard equation is also considered.