Objective To explore the mediating role of perceived social support on the relationship between work pressure and presenteeism in ICU nurses. Methods A total of 403 ICU nurses from secondary and above hospitals in Ningxia Hui Autonomous Region were selected by convenient sampling method in February 2023，and evaluated by general demographic data questionnaire，Perceived Social Support Scale，Chinese Nurses Stressor Scale， and The Stanford Presenteeism Scale. AMOS 23.0 software was used to establish a model and conduct path analysis. Results The scores of work pressure，perceived social support and presenteeism were （99.45 ±19.22）， （58.94 ±15.04） and （17.33 ±4.49），respectively. The results of structural equation model showed that the work pressure of ICU nurses had a positive predictive effect on presenteeism （β=0.16，P<0.01），and perceived social support had a negative predictive effect on presenteeism （β=-0.04，P<0.01）. There was a partial mediating effect between work pressure and presenteeism in ICU nurses （indirect effect size was 0.016），and the effect contribution was 9.09%. Conclusion The current situation of ICU nurses’ presenteeism in Ningxia is quite severe. ICU nurses’ perceived social support plays a partial mediating role between work pressure and presenteeism. Managers can mobilize ICU nurses to fully tap and use their perceived social support resources to relieve their work pressure and reduce hidden absenteeism from the perspective of work resources.