The synthesis of 7-arylidene cephalosporanates for ${eta}-lactamase$ inhibitor was described. The reactions of substituted benzyl halides $[1]{sim}[3]$ with triphenylphosphine gave triphenylphcsphonium chlorides $[4]{sim}[6]$. These phosphonium salts were treated with n-butyllithium to give ylides, which were reated with 7-oxocephalosporanate [7] by Wittig reaction to afford the 7-exomethylene cephalosporanates $[8]{sim}[10]$. These cephalosporanates were oxidized to cephalosporanate sulfones $[11]{sim}[13]$ with mCPBA. The deprotection of benzhydryl cephalosporanate $[8]{sim}[13]$ with $AlCl_3$ and $NaHCO_{3}$ gave sodium salts of 7-arylidene cephalosporanates $[14]{sim}[19]$.