The invention discloses a process for producing an environment-friendly plasticizer employing a conical fluidized bed and a device thereof. Isooctyl alcohol and terephthalic acid are fed to a reaction kettle of the conical fluidized bed after being pulpified by a grinding miller according to the mass ratio of alkyd materials being (2.4-2.7) to 1. The process comprises the following steps: firstly, heating and dewatering, and adding 0.3-0.5% of catalyst after the temperature of the reaction kettle achieves 170-180 DEG C; driving the material to move from top to bottom inside the fluidized bed under the effect of a circulating pump, so as to form a boiling state; bringing out the moisture generated in reaction by the evaporated isooctyl alcohol, and condensing and collecting into a receiving tank; rapidly layering water and the isooctyl alcohol in the receiving tank; returning the isooctyl alcohol to the reaction kettle of the conical fluidized bed to participate in reaction again through a reflux pump; and achieving an esterification reaction endpoint when the acid value of esterifying liquid is reduced below 0.2 mg/g. Compared with the traditional reaction kettle production process, the esterification reaction rate of the process disclosed by the invention is increased by 20-30%, and the energy consumption is reduced by over 30%.