Photocatalytic degradation kinetics of acetamiprid was studied by both of single-variable-at-a-time (SVAT) and central composite design (CCD) experiments based on four factors, such as catalyst dosages, substrate concentration, temperature and pH values. The results indicated that degradation of acetamiprid followed pseudo first-order kinetics by Langmuir-Hinshelwood model, increased with the increasing of temperature and the decreasing of substrate concentration. The photocatalytic degradation kinetic rate of acetamiprid was low in acid solutions, while high in weak acidic and alkaline solutions. After studying the synergistic effects of these four classic parameters, the optimal experiment conditions for photocatalytic degradation of acetamiprid were obtained as follows: TiO2 at 2.30 g x L(-1), initial acetamiprid concentration of 90.0 μmol x L(-1), temperature of 37.5 degrees C and pH value at 5.0. Lastly, 7 degradation intermediates of acetamiprid were detected during photocatalytic process by HPLC, and 6 of them exhibited more polar than the parent molecule.