As an emerging technology, low-temperature plasma (LTP) is widely used in medical fields such as sterilization, wound healing, stomatology, and cancer treatment. Great achievements have been made in tumor therapy. In vitro and in vivo studies have shown that LTP has anti-tumor effects, and LTP is selective to tumor cells. Studies in recent years have found that LTP can activate dendritic cells (DC), macrophages, T cells, and other immune cells to achieve anti-tumor effects. This paper reviews the current status of tumor immunotherapy, the application of LTP in antitumor therapy, the activation of antitumor immunity by LTP, the possible mechanism of LTP in antitumor immunity, and meanwhile analyses the prospect of applying LTP in tumor immunotherapy.