This study is mainly focused on micellar effect of tetradecyltrimethyl ammonium bromide(TTABr) solution including alkylbenzimidazole(R-BI) on dephosphorylation of diphenyl-4-nitrophenylphosphinate(DPNPIN) in carbonate buffer(pH 10.7). Dephosphorylation of DPNPIN is accelerated by BI⊖ ion in 10-2 M Carbonate buffer(pH 10.7) of 4×10-4 M TTABr solution up to 80 times as compared with the reaction in Carbonate buffer by no benzimidazole(BI) solution of TTABr. The value of pseudo first order rate constant(kψ) of the reaction in TTABr solution reached a maximum rate constant increasing micelle concentration. The reaction mediated by R-BI⊖ in micellar solutions are obviously slower than those by BI⊖, and the reaction rate were decreased with increase of lengths of alkyl groups. It seems due to steric effect of alkyl groups of R-BI⊖ in Stern layer of micellar solution. The surfactant reagent, TTABr, strongly catalyzes the reaction of DPNPIN with R-BI and its anion(R-BI⊖) in Carbonate buffer(pH 10.7). For example, 4×10-4 M TTABr in 1×10-4 M BI solution increase the rate constant(kψ=99.7×10-4 1/sec) of the dephosphorylation by a factor ca. 28, when compared with reaction(kψ=3.5×10-4 1/sec) in BI solution(without TTABr). And no TTABr solution, in BI solution increase the rate constant(kψ=3.5×10-4 1/sec) of the dephosphorylation by a factor ca. 39, when compared with reaction (kψ=1.0×10-5 1/sec) in water solution(without BI).