Grain size of MAPbI(3) and thickness of mesoporous TiO2 (mp-TiO2) film are found to influence current-voltage (J-V) hysteresis, where the J-V hysteresis is alleviated as grain size increases and thickness of mp-TiO2 varies. In this work, a low-cost and high-efficiency additive 4-methylbenzenesulfonic acid (4-MSA) is introduced into perovskite precursor solution to improve the performances of perovskite solar cells (PSCs) and reduce the device hysteresis. By adjusting 4-MSA concentration, the fabricated PSC shows the best power conversion efficiency (PCE) of 17.58% (J(sc) = 23.15 mA cm(-2), V-oc = 1.04 V and FF = 0.73) and a hysteresis index (HI) of 0.048 with a fixed device area of 0.15 cm(2) under illumination of AM 1.5G (100 mW cm(-2)). The significantly improved device performances maybe due to the fact that the carriers more easily be collected for larger grain sizes and fewer grain boundaries by doping 4-MSA into perovskite precursor solution. Furthermore, the sulfonic group is chemically bonded to mp-TiO2 and phenyl backbone has p-conjugated structure, which benefits electron transfer. (C) 2017 Elsevier B.V. All rights reserved.