Although perovskite solar cells have achieved great development in the device performance, the device stability is still a crucial issue hinder the further development. The ion migration is a main reason for the poor stability of the perovskite solar cells. Here, we use a cross-linking material, polydimethylsiloxane (PDMS) to dope the perovskite layer to improve the operational stability. We systematically studied the effect of curing agent content in PDMS on the device performance and stability. The characterization of perovskite film indicates that PDMS primarily doped in the perovskite layer and as well as enriched at the surface of perovskite film. Doping of PDMS promoted the crystallization of perovskite phase, leading to increase of short circuit density (JSC) and fill factor (FF) of the solar cells. In addition, PDMS doping improved the operational stability of device due to the sup-pressing the migration of iodide ions during aging. Moreover, the higher content of curing agents used in PDMS, the better stability of the devices. This work indicates PDMS doping the perovskite layer with a suitable content of curing agent can produce a better operational stability of the perovskite solar cells.