The invention belongs to the field of 
chemistry, and relates to a synthetic method of asymmetrical 
thioether. The synthetic method comprises the following steps of (a) under the condition of 
catalysis of tetrabutyl 
ammonium halide, enabling a structural compound as shown in a formula (I), a structural compound as shown in a formula (II) and 
sulfur oxonium salt to react in a 
solvent so as to obtain the asymmetrical 
thioether with a structure as shown in formula (III), wherein R1 is selected from phenyl, substituted phenyl, naphtyl, substituted naphtyl, thienyl, or substituted thienyl; R2 is selected from 
hydrogen, phenyl, substituted phenyl, naphtyl, substituted naphtyl, thienyl or substituted thienyl; or R1, R2 and C connected with R1 and R2 form 
fluorene or 
thioxanthene; R3 is selected from 
hydrogen or an 
alkyl group; R4 is selected from 
hydrogen, phenyl, substituted phenyl, naphtyl, substituted naphtyl, thienyl or substituted thienyl; R5 is selected from hydrogen; or R4, R5 and C connected with R4 and R5 form the 
fluorene or the 
thioxanthene; R6 is selected form the 
alkyl group or the substituted 
alkyl group; and X is selected from C1, Br or I.