Most of conventional methods for producing particle include crystallization, milling and drying with spray and frigid dryers are mechanical methods. These methods contain problems such as changing the nature, large-scale distribution of particle size, environment contamination, the presence of the solvent in the product. Nowadays to solve these problems, supercritical technology are used to disperse particles. The solubility of many of the drug compounds in the supercritical fluid of carbon dioxide is very low therefore, the supercritical fluid can be used as the supercritical anti-solvent for the production of micro and nanomaterials. One of the methods for producing micro and nanoparticles is to increase the dispersion of the solution to the supercritical solvent. In this method, a two-channel coaxial nozzle is used through which solution enters from the inner channel and supercritical crisis enters from the outer channel. These two streams are mixed in a small region of the nozzle called mixing length. The incremental process of soluble dispersion due to the high difference in mass and the high mass transfer and the increase in anti-solvent to solution in the solution mixing length produces ultra-saturation solution which creates small uniform particles. In this thesis, the modeling of this process has been done in a two-channel nozzle with software Ansys Fluent 16.2. The main objectives of this thesis are to formulate modeling and simulation of the community for the aforementioned process for the two used nozzles, the validation of the model by comparing the target subject (the average of the particle diameter) with the experimental results, identifying the effective parameters, designing the experiment with the software Minitab17, the optimization of operating conditions, and then comparing the target subject (the average of the particle diameter) is in optimal operational conditions. In the end by comparing the simulation results with a special laboratory case (beta-carotene drug), the true simulation is evaluated. Then a mathematical model matches the simulation data so that the model matches the experimental data. Considering the different input conditions applied to the model program, the results show the relative error in the range of 1-30%. Due to the fact that the model with less error is not available at present, the results of this model can be used to study the effects of direct electricity parameters on the average of the particle diameter. Also, by using this model, we can study the effect of independent parameters and thermodynamic profiles in thin length. In the results of the model according to different input conditions, microparticles with an average diameter of 40,1 - 2,37 micrometers for the Vladimir test and 25,63-1,886 micrometers for Hanna and York testing will be made that is consistent with laboratory results. The results show that the carbon dioxide input, Concentration and pressure is directly related to the particle size so that their increase will boost the diameter of the particle. The solution inlet flow also has an indirect relationship so that the increase in the solution inlet flow decreases the diameter of the particle. There was no particular trend for temperature variations with particle diameter that was consistent with laboratory results. The results showed that in the comparison of the used nozzle in the experiment of Vladimir with the Hanna and York, the Hanna and York nozzle produces smaller diameter particles But the amount of beta carotene production is lower with this nozzle. Keywords: modeling, simulation, Optimization, Supercritical antisolvent fluid, beta carotene, Solution enhanced dispersion by supercritical fluids