The present paper proposes a numerical simulation method of two-phase flow for analysing LCO₂ (liquid CO₂) droplet plume at the middle depth of the deep ocean. This method contains the drift velocity of the LCO₂ droplets and the dissolution of CO₂ into the sea water as notable features. After being validated by comparing well with laboratory-scale air-bubble-plume experiments in literature, it is applied to the simulation of LCO₂ plume in the deep ocean. The results indicate some new phenomena contradicting currently widespread conceptions : the present simulation suggests, firstly, that the dense CO₂ solute does not peel from the LCO₂ plume and, instead, forms the fountain-like flow against, the rising plume and. secondly, that the maximal vertical distance for the complete dissolution of the LCO₂ droplets does not vary very much depending on the initial droplet size.