As a versatile Chinese herb, Ganoderma lucidum (Leyss. ex Fr.) Karst (G. lucidum) has been applied to treat multiple diseases in clinics and improve the quality of life of patients. Among all of its extracts, the main bioactive components are G. lucidum polysaccharides (GLPs), which possess many therapeutic effects, such as antitumor, immunoregulatory, anti-oxidant, antidiabetic, antibacterial, and antifungal effects and neuroprotection activities. This review briefly summarized the recent studies of the pharmacological rationales of GLPs and their underlying molecular signaling transmission mechanisms in treating diseases. Until now, the clear mechanisms of GLPs for treating diseases have not been reported. In this review, we used the keywords of "Ganoderma lucidum polysaccharides"and "tumor"to search in PubMed (years of 1992-2020), then screened and obtained 160 targets of antitumor activities in the literatures. The network pharmacology and mechanism framework were employed in this study as powerful approaches to systematically analyze the complicated potential antitumor mechanisms and targets of GLPs in cancer. We then found that there are 69 targets and 21 network pathways in "Pathways in cancer". Besides, we summarized the effects of GLPs and the models and methods used in the research of GLPs. In conclusion, GLPs have been studied extensively, but more in-depth research is still needed to determine the exact mechanisms and pathways. Therefore, this review might provide new insights into the vital targets and pathways for researchers to study the pharmacological mechanisms of GLPs for the treatment of diseases.