In order to determine the apron U-zone spatial efficiency assessment index system and the importance of its indexes, the evaluation index system of apron U-zone spatial efficiency was established from two dimensions of apron design and apron operation. Based on this, a spatial efficiency assessment method based on the paradigm gray correlation-dynamic efficacy coefficient method for apron U-zones was proposed. And the U-zone apron corresponding to the terminal buildings of 10 domestic large-scale transportation airports was calculated as an example, and the weights of each index affecting the spatial efficiency of the apron's U-zone were obtained as well as the spatial efficiency scores of the U-zone apron corresponding to the terminal buildings of each airport. It is proposed that three indexes should be emphasized in the design of U-zone, including the number of gates at the edge of the finger corridor, the depth of the finger corridor and the length of the bottom edge of the U-zone. The results show that this method can scientifically analyze the factors affecting the spatial efficiency of the apron U-zone, effectively judge the spatial efficiency of the U-zone in different configurations.