Supercritical fluid extraction is an advanced extraction technique that suitable for heat sensitive and active compound material from plants and herbs. Understanding the effect of extraction parameters on mass transfer coefficient at solid and fluid phase can determine the dominating extraction regime thus performance of the extraction may be enhanced. The aim of this research was to determine the mass transfer coefficient in solid and fluid phase using kinetic modelling approach. Grounded betel nuts were treated with supercritical carbon dioxide with 5 methanol as co-solvent to determine its mass transfer coefficient in solid and fluid phase for the following extraction conditions; pressure, 20 to 30 MPa; temperature, 50 to 70 °C; and flow rate, 2 to 4 mL/min. Simplified Sovová model was coupled with Broken and Intact Cell model to determine the mass transfer coefficients. Results show the mass transfer coefficients of solid phase and liquid phase are in the ranges of 0.00015 to 0.00353 m3/min and 0.3497 to 3.9623 m3/min, respectively. The overall absolute average relative deviation was observed to be 7.39. © Universiti Malaysia Pahang, Malaysia.