Clutch control method used in downshifting process of transmission of automatic transmission system

The invention relates to a clutch control method used in the downshifting process of a transmission of an automatic transmission system. The clutch control method includes the steps that firstly, a vehicle signal is acquired; secondly, whether upshifting or downshifting of a vehicle is needed or not is judged according to the acquired vehicle signal; thirdly, if upshifting or downshifting is needed for the vehicle, upshifting or downshifting is judged according to a gear shifting control strategy; fourthly, the work condition of upshifting or downshifting needed for the vehicle is controlled according to the gear shifting control strategy, and separation control of a clutch is performed; fifthly, gear shifting control is performed according to separation of the clutch; and sixthly, after it is confirmed that gear shifting succeeds, combination control of the clutch is performed. By means of the technical scheme, deferential control over the clutch in the AMT transmission downshifting process is achieved, and the service life of a gear shifting synchronizer is prolonged.