Objective : The CRISPR / Cas9 technology was applied to construct PDE4D homozygous knockout mice to provide a basis for in-depth investigation of PDE4D gene function and mechanism of action． Methods: A vector was constructed for PDE4D gene exon 4，5 microinjected into fertilized eggs of C57BL /6J mice，and PDE4D －/ - mice were obtained after maternal breeding and offspring mating，and the mice genotypes were determined by PCR product sequencing and genotype identification techniques．Changes in morphology and function of the major organs of the mice were detected using an ultrasound imaging system and H＆E staining，and the expression of PDE4D protein in the mice was verified by Western blot assay. Results : The PDE4D －/ － mouse genotype was stably inherited， the mice were small，and there were no obvious morphological and histological changes in the major organs in vivo. The PDE4D expression was reduced or largely absent in the major tissues of PDE4D heterozygous or pure knockout mice，and the knockout effect was better． Conclusion PDE4D －/ － mice were successfully established using CRISPR / Cas9 technology，and no significant physiological abnormalities were found，which could be used for disease pathogenesis and drug research using PDE4D as the target.