The critical temperatures (T-c) and critical pressures (p(c)) of five binary mixtures of n-butanol + n-alkane (C = 6, 7, 8, 9, 10) as well as two ternary mixtures (n-butanol + hexane + heptane and n-butanol + heptane + octane) were measured over the whole concentration range using a flow method apparatus. The T-c of binary mixtures which contain heptane, octane, and nonane display a significant nonideality. The p(c) of binary mixtures increase with the increasing mole fraction of n-butanol and p(c)-x(1) curves rise up more obviously in richer n-butanol regions. The trends of the T-c-w(1) curves of two ternary mixtures slightly change with the increasing mass fraction of corresponding n-alkane components in mixtures. By using the Redlich-Kister equations, average absolute deviations (AADs) of binary mixtures were less than 0.09% and 0.31% for T-c and p(c), respectively. T-c and p(c) of ternary mixtures were correlated using Cibulka's equations and Singh-Sharma's equations.