Method for longitudinally parking a motor vehicle in at least semi-autonomous parking process into a longitudinal parking space, wherein at least one longitudinal boundary of the longitudinal parking space and one lateral boundary (13, 14) of the longitudinal parking space of the longitudinal parking space are sensed by means of a sensing device of the motor vehicle, comprising the steps: a) determining a setpoint parking position in the longitudinal parking space with a longitudinal distance between a motor vehicle component of the motor vehicle and the longitudinal boundary of the longitudinal parking space and with a lateral distance between a motor vehicle component of the motor vehicle and the lateral boundary of the longitudinal parking space as a function of the sensed longitudinal parking space boundaries (12, 13, 14) and as a function of a longitudinal distance threshold value and a lateral distance threshold value; b) determining a parking trajectory (Z1, Z2) for the setpoint parking position as a function of at least the distance threshold values (A1, A2); c) moving the motor vehicle along the parking trajectory (Z1, Z2) and further sensing of the distance at least from the longitudinal boundary of the longitudinal parking space during the parking process; d) determining a currently reachable parking position of the motor vehicle as a function of at least the distance, sensed during the parking process, from the longitudinal boundary of the longitudinal parking space; characterized by the steps: e) comparison of the currently reachable parking position with the setpoint parking position when a predetermined position of the motor vehicle is reached during the parking process; f) reducing the longitudinal distance threshold value if the currently reachable parking position differs from the setpoint parking position; g) determining a new parking partial trajectory as a function of the lateral distance threshold value and the reduced longitudinal distance threshold value (A1'); and h) moving the motor vehicle along the new parking partial trajectory. a) determining a setpoint parking position in the longitudinal parking space with a longitudinal distance between a motor vehicle component of the motor vehicle and the longitudinal boundary of the longitudinal parking space and with a lateral distance between a motor vehicle component of the motor vehicle and the lateral boundary of the longitudinal parking space as a function of the sensed longitudinal parking space boundaries (12, 13, 14) and as a function of a longitudinal distance threshold value and a lateral distance threshold value; b) determining a parking trajectory (Z1, Z2) for the setpoint parking position as a function of at least the distance threshold values (A1, A2); c) moving the motor vehicle along the parking trajectory (Z1, Z2) and further sensing of the distance at least from the longitudinal boundary of the longitudinal parking space during the parking process; d) determining a currently reachable parking position of the motor vehicle as a function of at least the distance, sensed during the parking process, from the longitudinal boundary of the longitudinal parking space; e) comparison of the currently reachable parking position with the setpoint parking position when a predetermined position of the motor vehicle is reached during the parking process; f) reducing the longitudinal distance threshold value if the currently reachable parking position differs from the setpoint parking position; g) determining a new parking partial trajectory as a function of the lateral distance threshold value and the reduced longitudinal distance threshold value (A1'); and h) moving the motor vehicle along the new parking partial trajectory.