Abstract: Objective To investigate the infection status and risk factors of multidrug resistant bacteria(MDRO) in patients with malignant tumors in a hospital. Methods A total of 1 280 patients with malignant tumor infection admitted to a hospital from January 2014 to December 2017 were divided into MDRO infection group(n=270) and non-MDRO infection group(n=1 010). Risk factors for MDRO infection in malignant tumor patients were analyzed by univariate and multivariate logistic regression. Results The incidence of MDRO infection was 21.09%(270/1 280) in 1 280 patients with malignant tumors. A total of 295 strains of multidrug-resistant bacteria were detected in 270 patients with MDRO infection. The top three strains were Acinetobacter Baumannii(31.19%), Pseudomonas Aeruginosa(23.05%) and Escherichia coli(19.32%). Univariate and multivariate logistic regression analysis showed that long-term bedridden(OR=2.804, 95% CI:1.725-4.364), invasive operation(OR=3.907, 95% CI:2.914-7.523), types of antibiotics used(OR=5.306, 95% CI:4.105-9.248), time spent using antibiotics(OR=3.117, 95% CI:2.208-6.731) and low albumin level(OR=2.105, 95% CI:1.286-3.740) were risk factors for MDRO infection in patients with malignant tumors. Conclusion There are many risk factors for MDRO in patients with malignant tumors. Effective prevention and control measures should be taken against these risk factors to reduce the incidence of MDRO infection.