Typhoon Khanun (2306) undergoes two significant turning tracks in its mid-to-late life cycle, posing substantial challenges to operational forecasting. This study analyzes the causes of the two abrupt track changes and forecast deviations using the operational typhoon track data from National Meteorological Center, numerical models output and ERA5 reanalysis data. The results are as follows. During the first abrupt track change, the southwest monsoon to the south of Typhoon Khanun intensifies and shifts northward, while the western North Pacific subtropical high to its east strengthens and extends to the south of the typhoon. The combination of these factors creates a deep southwesterly steering environmental field, leading to the abrupt track change of Typhoon Khanun (stagnation near the sea followed by a westward turn). The second abrupt track change occurs due to the re-intensification and westward extension of the subtropical high to the east of Typhoon Khanun, causing it to first decelerate and then turn northward. Prior to the first abrupt track change, numerical models underestimate the intensity of the subtropical high core, leading to weaker pressure gradient and thus weaker monsoon channel winds to the south, and the rapid movement of Typhoon Khanun causes a detachment from the monsoon channel, resulting in the failure of the forecast for the first abrupt track change. During the second abrupt track change, the models overestimate the intensity of an upper tropospheric cold low to the northeast of Typhoon Khanun, suppressing the subtropical high’s westward extension and inducing a failure of the forecast for the track change. The findings inspire a new approach for the subjective forecasting of typhoon tracks: by integrating the correction of typhoon’s moving speed with changes in the steering flow, the typhoon’s direction can be simultaneously adjusted and thus the track forecasts improve.