Objective To evaluate the relationship between Maternal Critical Care Working Group level of care (MCCWG-LOC) and specific pregnancy outcomes applying the levels of care (LOC) evaluation system recommended by the MCCWG in pregnant women admitted to the intensive care unit (ICU), and to compare MCCWG-LOC and two other early warning scoring systems (acute physiology and chronic health evaluation Ⅱ [APACHE Ⅱ] and obstetric early warning score [OEWS]). Methods A total of 363 pregnant women admitted to the ICU of Suzhou Municipal Hospital from January 2015 to December 2018 were selected for a single center retrospective cohort study. According to the hierarchical monitoring level of MCCWG-LOC, they were divided into the level 1 monitoring group (182 cases), the level 2 monitoring group (103 cases) and the level 3 monitoring group (78 cases). The scores of APACHE Ⅱ, OEWS and specific pregnancy outcomes were compared among the three groups. Further, the level 1 and 2 monitoring groups were taken as the non intensive care group and the level 3 monitoring group was taken as the intensive care group. The discrimination ability of APACHE Ⅱ and OEWS early warning scoring systems for ICU pregnant women in the MCCWG-LOC evaluation system was evaluated by area under curve (AUC) of the receiver operating characteristic(ROC). Results During the study period, 363 pregnant women were admitted to ICU (ICU admission rate was 0.46%)and 3 pregnant women died (maternal mortality rate was 3.83/100 000). Among them, 276 cases (76.03%) were admitted for direct obstetric reasons and 87 cases (23.97%) were admitted for indirect obstetric reasons. Three maternal deaths occurred in the level 3 monitoring group. The total length of stay and ICU stay in the level 3 monitoring group were longer than those in the level 1 and 2 monitoring groups, and the perinatal loss rate and hospitalization expenses in the level 3 monitoring group were higher than those in the level 1 and 2 monitoring groups, the differences were statistically significant (P＜0.05). The APACHE Ⅱscore, APACHE Ⅱpredicted mortality and OEWS score in the level 3 monitoring group were higher than those in the level 1 and 2 monitoring groups, the differences were statistically significant (P＜0.05). Pairwise comparison showed that the OEWS score of the level 3 monitoring group was higher than that of the level 1 and 2 monitoring group, and the OEWS score of the level 2 monitoring group was higher than that of the level 1 monitoring group, the differences were statistically significant (P＜0.05). The APACHE Ⅱscore and APACHEⅡpredicted mortality in the level 3 monitoring group were higher than those in the level 1 and 2 monitoring group, the differences were statistically significant (P＜0.05). There was no significant difference in APACHE Ⅱscore and APACHE Ⅱpredicted mortality between the level 1 monitoring group and the level 2 monitoring group (P＞0.05). APACHE Ⅱand OEWS had a certain ability to distinguish pregnant women in intensive care (ROC AUC=0.808 [95%CI:0.748-0.868]) and 0.847 [95%CI:(0.799-0.894)], and OEWS is higher than APACHE Ⅱ. Conclusion MCCWG-LOC evaluation system is directly related to disease severity, and is highly consistent with the early warning scoring system widely recognized and applied in clinic. The application of this simple evaluation system based on organ support can stratify the monitoring level of obstetric critical patients and improve the comprehensive treatment ability of critically ill pregnant women.