A data sharing and instruction operation control method, and a system are provided. The method includes: a first terminal establishes a communication connection to a second terminal; the second terminal displays a user interface of a camera application, wherein the user interface includes a photographing parameter adjustment option; the second terminal sends the user interface including the photographing parameter adjustment option to the first terminal; the first terminal may tap the photographing parameter adjustment option on the user interface, and send a control instruction to the second terminal; and the second terminal adjusts a photographing parameter of the camera application based on the control instruction, and displays a user interface obtained after the parameter adjustment.