Selecting excellent parents and cross combinations, determining the optimal pollination period and exploring the cross compatibility among ornamental crabapple cultivars is valuable to provide references for the breeding of new cultivars. In this study, 15 crabapple cultivars with different ornamental characteristics were selected, the pollen viability and anther pollen quantity were determined by in vitro culture method and suspension method, respectively. Then their male fertility was evaluated. The stigma receptivity at different days was determined by benzidine-hydrogen peroxide method, the growth and fertilization of pollen tubes after pollination were observed by fluorescence microscopy, and the fruit setting of 5 cross combinations were studied by artificial controlled pollination. The results were as follows:（1）The male fertility of 15 cultivars could be divided into 4 types: male sterile, low fertility, medium fertility and high fertility according to the pollen viability. Among them, 6 cultivars such as ‘Indian Summer’ and ‘Winter Red’ were high quality male parents. （2）The stigma receptivity showed a law of "weak-strong-weak" from 1 day before flowering to 6th day after flowering, and the 3rd day was the optimal pollination period. （3）The pollen began to germinate at 4~8 h and fertilized at 48-96 h after pollination. （4）There was a significant positive correlation between pollen fertility, stigma receptivity and fruit setting rate and seed plumpness rate. Besides, the peak period of fruit drop was within 2 months after pollination, then the fruit setting rate tended to be stable. ‘Winter Red’ × ‘Indian Summer’ and ‘Strawberry Jelly’ × ‘Indian Summer’ were high fruiting rate cross combinations. These results showes that ornamental crabapple is dichogamous, parents with high fertility are the key to the success of cross, and the main reason for the incompatibility of crabapple is post-fertilization disorder in this study.