Objective To investigate whether the computed tomography（CT） signs of biochemically negative paragangliomas and pheochromocytomas （PPGLs） differ from those of biochemically positive PPGLs and whether there are differences in CT signs between different phenotypes of biochemically positive PPGLs. Methods A retrospective analysis was performed for the preoperative abdominal contrast-enhanced CT images of 131 patients with PPGLs，including tumor location，size，shape，cystic change and necrosis，fluid-fluid stratification，calcification，nodular centripetal enhancement，large blood vessels in tumor，enhancing capsule，absolute percentage washout，and relative percentage washout. According to biochemistry，the patients were divided into biochemically positive group and biochemically negative group，and the biochemically positive group was further divided into norepinephrine phenotype group，adrenaline phenotype group，and dopamine phenotype group. CT signs were compared between each group and different phenotypes. Results Compared with the biochemically negative group，the biochemically positive group had significantly larger PPGLs（Z=-2.064，P=0.039） and a significantly higher proportion of patients with cystic change and necrosis（χ² =6.610，P=0.010） or nodular centripetal enhancement（χ² =3.909，P=0.048），and compared with the norepinephrine phenotype group，the epinephrine phenotype group had significantly larger PPGLs（Z=-2.036，P=0.042） and a significantly higher proportion of patients with enhancing capsule（χ² =7.242，P=0.007）. Conclusion The CT signs of tumor size，cystic change and necrosis，and nodular centripetal enhancement can help with the diagnosis of biochemically negative PPGLs before surgery，and tumor size and enhancing capsule can help to explain the mechanism of different clinical manifestations of PPGLs with norepinephrine phenotype or epinephrine phenotype.