Disclosed are a ball-pitching control method of a pitching machine in a baseball practice system that is capable of automatically compensating for inclination of the pitching machine, which may occur depending on the installation environment of the pitching machine, based on the result of sensing performed by a sensing device for sensing a pitched ball or a hit ball without using a separate sensor or measurement device and that is capable of automatically self-correcting the displacement of the pitching machine from the original position thereof or the corrected position thereof over time due to external impact applied to the pitching machine or a manager's inaccurate correction of the pitching machine by analyzing the results periodically sensed by a sensing device and the cumulative results of set ball pitching information of the pitching machine, and a baseball practice system using the same.