<p>Hematologic neoplasms are hard to cure, and patients face a lifelong treatment burden. Social support is vital for alleviating it, yet the influencing mechanism is unknown. Illness perception might play a mediating role among this association. To explore the mediating effect of illness perception between social support and treatment burden in hematologic neoplasms patients. From December 2023 to July 2024, patients with hematologic neoplasms admitted to the hematology department of a tertiary hospital in Jiangsu Province were surveyed via convenience sampling. General information questionnaire, Treatment Burden Questionnaire(TBQ), The Brief Illness Perception Questionnaire(BIPQ) and s Social Support Rate Scale(SSRS )were used for the survey. A total of 206 participants were recruited for the survey, with an overall TBQ score of (75.33 ± 30.91), SSRS score of (33.17 ± 4.52), and BIPQ score of (50.03 ± 12.37). Social support was negatively correlated with illness perception (<i>β</i>= -0.185, <i>p</i> = 0.005) and treatment burden (<i>β</i>=-0.198, <i>p</i> &lt; 0.001), and illness perception was positively correlated with treatment burden (<i>β</i> = 0.363, <i>p</i> &lt; 0.001). Illness perception partially mediated the relationship between social support and treatment burden, with an indirect effect of 25.28%.Treatment burden and illness perception in hematological neoplasms patients are high, while social support is at a medium level. Healthcare professionals should take effective steps to boost social support and reduce negative perceptions, aiming to ease patients’ treatment burden.</p>