Objective To understand the status quo of character strengths, perceived social support and coping style in patients with malignant tumor, and to explore the relationship among them. Methods A total of 235 patients with malignant tumor were selected by convenience sampling method, then they were investigated by utilizing a general information questionnaire, the Three-Dimensional Inventory of Character Strengths (TIS), the Perceived Social Support Scale (PSSS) and the Medical Coping Modes Questionnaire (MCMQ). Results The total scores of TIS and PSSS were (52.40±4.34) and (62.55±7.42), and the subscales scores of confrontation, avoidance and acceptance-resignation were (17.57±3.33), (16.08±2.49) and (8.70±2.12), respectively. Character strengths was positively correlated with perceived social support, confrontation and avoidance (all P<0.05), while acceptance-resignation was negatively correlated with character strengths and perceived social support (both P<0.05). Perceived social support played a partial mediating role between character strengths and acceptance-resignation, and the indirect effect accounted for 21.04% of the total effect. Conclusion Character strengths in patients with malignant tumor is at a medium level, while perceived social support is in high level, and the most common coping style is avoidance. Character strengths can affect the coping style of patients through perceived social support. It is recommended that medical staff develop interventions based on character strengths, mobilize and use the patients′ social support system, and promote patients to actively cope with the disease.