Objective To investigate the clinical characteristics and risk factors of immature hematomas in patients with primary intracerebral hemorrhage. Methods Patients with primary intracerebral hemorrhage who admitted in West China Hospital of Sichuan University between March 2012 and January 2021 were retrospectively analyzed. Brain CT scan was used to evaluate the presence of immature hematomas, as well as hematoma volume and the morphological features such as the number of hematoma projections or satellite foci, and finger-like projections. Imaging markers of cerebral small vessel disease such as lacunes, microbleeds, white matter hyperintensities (WMH), and enlarged perivascular space were evaluated on MRI. Mature hematomas were defined when the hematomas were completely homogeneous, without any irregularity or hypodensity, otherwise the hematomas were regarded as immature. Patients were divided into two groups: mature hematomas and immature hematomas. Multivariate Logistic regression was used to analyze the risk factors of immature hematomas. Results A total of 170 patients were included. Among them, there were 121 males (71.2%). The average age was (60.9±13.3) years old, and 129 cases (75.9%) had immature hematomas. The comparison between the mature hematomas group and the immature hematomas group showed that higher admission National Institutes of Health Stroke Scale score, larger hematoma volume, hematoma volume >30 mL, more hematoma projections or satellite foci, lower incidence of round or oval hematomas, cerebral small vessel disease score, lower WMH burden, and lower burden of cerebral small vessel disease were associated with the occurrence of immature hematomas. The results of multiple logistic regression analysis showed that lower incidence of round or oval hematomas, lower incidence of WMH, and lower periventricular WMH scores were associated with the occurrence of immature hematomas after adjusting for age, gender, hypertension, diabetes, smoking, alcohol consumption, admission National Institutes of Health Stroke Scale score, and hematoma volume. Conclusion Lower incidence of round or oval hematomas and lower periventricular WMH burden are associated with immature hematomas.