Abstract: To realize fix-point landing with lossless recovery for aircraft and controllable fix-point airdrop for person or materials,one kind of GNC (guidance navigation and control) software for big controllable parafoil had been designed.The obtained software,running at onboard control computer of GNC system for a big or middle parafoil,adopted a multi-segment control algorithm and modularized software structure.It could fly either in automatic mode or in manual remote mode.The present software could decode and conduct calculation based on the data provided by GPS and output control signals automatically to operate contracting or releasing both the right and left parafoil rope.This realized the landing to the area as predicted.The present software had been verified by hardware and software association test,whose results revealed that the present software met the requirement for fix-point recovery and landing of controllable parafoil.The present software exhibited promising application in precision airdrop,fix-point recovery and landing for aircraft,weapon,and launch vehicle of freight rocket.