Objective To observe the effects of Tai-ji exercise motor imagery on the walk function of patients with hemiplegia after stroke. Methods A total of 40 hospitalized patients with hemiplegia after stroke who met the inclusion criteria were selected and divided into the group A (n=20) and group B (n=20) by the cross control design method. The experiment was divided into phaseⅠ (week 1 to 3), phaseⅡ (week 4 to 5), and phase Ⅲ (week 6 to 8). For group A, patients were treated with routine rehabilitation training combined with Tai-Ji exercise motor imagery therapy at the phase Ⅰ and routine training at the phase Ⅲ. For group B, patients were treated with routine rehabilitation training at the phase Ⅰ and routine training combined with Tai-Ji exercise motor imagery therapy at the phase Ⅲ. Phase Ⅱ was the washout period and patients of two groups were not treated with routine rehabilitation training or motor imagery therapy during phase Ⅱ. The walk function of patients was evaluated by the lower extremity part of Fugl-Meyer motor assessment (FMA), functional ambulation category (FAC), and Tinetti Gait Assessment (TGA) before the experiment and 3, 5, and 8 weeks after the intervention. Results Scores of three items of the group A and B increased significantly after the intervention. The differences of scores of 3, 5, and 8 weeks after the intervention were statistically significant (P<0.05). The differences of scores of three items of the group A and B before the intervention were not statistically significant (P>0.05). Scores of three items of the group A 3 weeks after the intervention were higher than those of the group B and the differences were statistically significant (P<0.05 or P<0.01). The differences of scores 5 weeks between the two groups after the intervention were not statistically significant (P>0.05). Scores of three items of the group B 8 weeks after the intervention were higher than those of the group A and the differences were statistically significant (P<0.05 or P<0.01). Conclusion With the increase of intervention time, Tai-ji exercise motor imagery therapy is more helpful for the recovery of walk function of patients with hemiplegia after stroke on the basis of routine rehabilitation training and improves the effect of rehabilitation training.