A longitudinal ultrasound-assisted grinding (LUVAG) alumina ceramics grinding force model and an LUVAG end grinding force model were developed in order to examine the influence of different parameters on the grinding force. Experiments were conducted to determine the effective cutting trajectory of grinding transient single abrasive grains and the effective removal volume of transient material. The experimental results showed that the tangential grinding force was positively correlated with table speed, grinding depth and wheel speed, the tangential grinding force was negatively correlated with ultrasonic amplitude, the forward grinding force was positively correlated with grinding depth and table speed, and the forward grinding force was negatively correlated with ultrasonic amplitude and wheel speed. The calculated results of the theoretical model of grinding force and the differential images showed that the experimental results and the calculated results could accurately reveal the influence of various factors on the trend of grinding force. By performing the extreme difference analysis on the grinding force data obtained from the LUVAG test, it was found that the grinding force was minimized when the ultrasonic amplitude was 12μm, the grinding wheel speed was 3500 r/min, the grinding depth was 5μm and the feed rate was 400 mm/min. Meanwhile, it is proved that the model can assist orthogonal experiments for factor screening and scheme optimization, which has important practical application value.