Effects of n-butanol addition on the sooting tendency and formations of C-1 and C-2 primary intermediates of n-heptane/air mixtures were studied in a micro flow reactor with a controlled temperature profile. Sooting tendency was investigated over equivalence ratios of 1.5-4.0 at a maximum wall temperature of 1300 K. Experimental observations indicated two types of flames: a flame alone (type I) or a flame with soot (type II). The critical sooting equivalence ratio, at which the flame switched from type I to type II, increased with the increase of butanol content in the fuel blend. Results show that the sooting tendency of n-heptane decreases as the amount of n-butanol is increased. Computational results obtained using the Chemical Reaction Engineering and Chemical Kinetics mechanism show fair agreement with measurement results obtained at equivalence ratio of 2.0 and the maximum wall temperature of 1166 K. The validity in initial-stage reaction progress of existing mechanisms was examined.