A method and device for controlling a walking assist device is disclosed. The method includes determining a first state variable for a gait state of a user wearing the walking assist device based on a gait of the user, obtaining a second state variable which is smoothed and time-delayed from the first state variable, obtaining a third state variable by applying a torque control variable to the second state variable, and determining an assist torque to be provided by the walking assist device based on the obtained third state variable.