The name of the district came from a canal,
Khlong Phasi Charoen (คลองภาษีเจริญ), linking
Tha Chin River to
Khlong Bangkok Yai. The canal project was initiated by
Phra Phasi Sombat Boribun (พระภาษีสมบัติบริบูรณ์), who later became
Phraya Phison Sombat Boribun (พระยาพิสณฑ์สมบัติบริบูรณ์). Originally Phasi Charoen proposed to fund the project in exchange for the right to collect tolls for passage. It was approved by King
Mongkut, however, with the fund given via tax deduction from the amount Phra Phasi Sombat Boriboon had to collect, thus making the canal toll-free. Construction began in 1866 and was completed in 1872 and the canal was named after the man who had overseen the project. The district was established as
Amphoe Phasi Charoen in 1899. It became
Khet Phasi Charoen in 1972. ==Administration==