Abstract： Objective To report one case of a collision tumor composed of intraventricular meningioma and astrocytoma and explore the cause.Methods A 39 - year - old male patient previously underwent excision of astrocytoma in the triangle area of the lateral ventricle and had good postsurgery recovery.The astrocytoma recurred in situ 6 years after the surgery,and it was also complicated with another lesion. The pathological results confirmed a collision tumor composed of intraventricular malignant meningioma and glioma In addition to reporting this case,we also performed a literature review of collision tumors.Results The patient recovered well after surgery to treat the recurrence and was given radiotherapy after discharge.Based on this literature review,we proposed several hypotheses on the formation of collision tumors.Conclusions We conclude that one possible reason of the collision tumor formed between the intracranial meningioma and the astrocytoma was the recurrence of astrocytoma - induced malignancy of arachnoid cells in the choroid plexus.