Objective To investigate the risk factors for spontaneous bacterial peritonitis (SBP) in patients with cirrhotic ascites, and to establish a new model for predicting the development of SBP. Methods A total of 215 patients who were diagnosed with cirrhotic ascites in Hebei General Hospital from September 2016 to September 2020 were enrolled, and according to the presence or absence of SBP, they were divided into SBP group with 55 patients and non-SBP group with 160 patients. Related clinical data were collected and albumin-bilirubin (ALBI) score, Model for End-Stage Liver Disease (MELD) score, MELD combined with serum sodium concentration (MELD-Na) score, and Child-Pugh score were calculated. The t -test or the Mann-Whitney U test was used for comparison of continuous data between two groups, and the chi-square test was used for comparison of categorical data between two groups; a multivariate logistic regression analysis was used to screen out independent risk factors, and the receiver operating characteristic (ROC) curve was plotted to evaluate the performance of ALBI score, procalcitonin (PCT), polymorphonuclear neutrophil (PMN) count in ascites, and the ALBI-PMN-PCT combined model in the diagnosis of SBP. Results Compared with the SBP group, the non-SBP group had a significantly higher concentration of Na + ( Z =-3.414, P =0.001) and significantly lower total bilirubin ( Z =-2.720, P =0.007), creatinine ( Z =-1.994, P =0.046), urea nitrogen ( Z =-2.440, P =0.015), C-reactive protein ( Z =-9.137, P < 0.001), PCT ( Z =-8.096, P < 0.001), prothrombin time ( Z =-1.969, P =0.049), international normalized ratio ( Z =-2.073, P =0.038), PMN ( Z =-8.292, P < 0.001), MELD score ( Z =-2.736, P =0.006), MELD-Na score ( Z =-3.188, P =0.001), Child-Pugh score ( Z =-3.419, P =0.001), and ALBI score ( t =-5.010, P < 0.001), and there were also significant differences between the two groups in the presence or absence of gastrointestinal bleeding or hepatic encephalopathy ( χ 2 =16.551 and 8.142, P < 0.001 and P =0.004). The multivariate logistic regression analysis showed that ALBI score (odds ratio [ OR ]=3.460, 95% confidence interval [ CI ]: 1.296-9.240, P =0.013), PMN ( OR =1.012, 95% CI : 1.007-1.017, P < 0.001), and PCT ( OR =6.019, 95% CI : 2.821-12.843, P < 0.001) were independent risk factors for SBP in patients with cirrhotic ascites. The ROC curve showed that ALBI, PCT, PMN, and ALBI-PMN-PCT had areas under the ROC curve of 0.711, 0.866, 0.875, and 0.934, respectively, in the diagnosis of SBP, with sensitivities of 50.91%, 73.36%, 72.73%, and 89.09%, respectively, and specificities of 86.87%, 81.25%, 100.00%, and 91.87%, respectively. The patients with ALBI-PMN-PCT > 0.272 had an increased risk of developing SBP. Conclusion The ALBI-PMN-PCT combined model has a high value in predicting the onset of SBP in patients with cirrhotic ascites.