Developing new therapeutic strategies that damage tumour cells without harming normal tissues is among the primary obstacles in chemotherapy. In this study, a novel β-glucuronidase-sensitive albumin-binding prodrug was designed and synthesized to selectively deliver the drug SN38 to tumour sites and maximize its efficacy. After intravenous administration, the prodrug Mal-glu-SN38 covalently bound to plasma albumin through the Michael addition, enabling it to accumulate in the tumour and release SN38 when triggered by extracellular β-glucuronidase. Compared to irinotecan, Mal-glu-SN38 displayed a slower plasma clearance and increased drug exposure over time. Moreover, Mal-glu-SN38 caused an increase in tumour-site accumulation of both the albumin-prodrug conjugate and free SN38 released from albumin conjugate when compared with irinotecan. After administration of multiple doses, Mal-glu-SN38 also significantly delayed the tumour growth, resulting in an impressive reduction or even disappearance of tumours (67% of mice cured) without causing any observable side effects.