The objective of this research is to estimate individual effect of various external parameters such as pressure, cooling rate, watercut and addition of mechanical impurities on change in wax appearance temperature (WAT) in oil. In this paper, complex multicomponent system like oil is replaced to simplified model solution, presented by wax in kerosene solution. Research methods in the study were visual method at high-pressure/hightemperature conditions and rheological method under ambient pressure. Experimental results shown that WAT grows with increase in concentration of wax in solution, increase in pressure, watercut, shear rate, addition of mechanical impurities and decrease in gap size of the measuring system (for rheological method). Numerical dependences of WAT in solution on the listed factors are received. Research data are explained by the thermodynamic processes proceeding in model solution. Influence of wax inhibitors addition on process of the crystal structure formation in model solutions and effective wax inhibitors is defined.