In this research, effect of bicomponent mixed surfactant was studied on drop interface coalescence phenomenon in ambient temperature. First basic chemical system was water and toluene and 0.01 gr of sodium dodecyle sulfate (SDS) and the second basic system was water and toluene and 0.01 gr of cethyl trimethy amonium bromide (CTAB). Various weight fractions of second surfactant including 2-heptanol (non-ionic) and aniline (cationic) added to each of these systems, respectively, in order to study the effect of mixed surfactant on coalescence time. It was shown that chemical systems including mixture of nonionic/anionic surfactant increased coalescence time. However, chemical systems including mixture of nonionic/cationic surfactant decreased coalescence time. If a mixture of anionic/cationic surfactant was considered, in terms of being weak or powerful cationic surfactant, coalescence time would have been decreased in the later and for mixture of ctionic/ctionic surfactant, coalescence time increased in small diameter and decreased in further diameter. Effect of sodium chloride (NaCl) on selected systems, including 40% CTAB in the basic system of water and toluene and SDS, 40% 2-heptanol in basic system of water and toluene and CTAB and 40% 2-heptanol in basic system of water and toluene and SDS was considered and it was shown that in general, coalescence time decreases.