Background and purpose Currently, the clinical benefits of liver cancer treatment are still limited. Emerging evidences have highlighted that paraptosis may be an effective strategy to threapy liver cancer. In our previous studies, compound 4a was found to induce paraptosis in cancer cells. Here, the characteristics of compound 4a induced paraptosis were further revealed, and for the first time, the target and related molecular mechanisms of compound 4a induced paraptosis in liver cancer were explored. Study design and methods The effect and mechanism of compound 4a on liver cancer cells both in vitro and in vivo. And the targets of compound 4a that triggering paraptosis, were identified and confirmed by using the technology of mass spectrometry-based drug affinity responsive target stability(DARTS), siRNA, and Cellular thermal Shift Assay(CETSA). Intracellular calcium concentration and protein distribution were detected by Cal520-AM and immunofluorescence, respectively. Results We found that compound 4a can effectively induce paraptosis-like cell death in liver cancer both in vitro and in vivo, and its effect is comparable to the first-line anti-liver cancer drugs oxaliplatin while with higher safety. We identified that Calreticulin(CRT) protein as a target of compound 4a, which causing cellular endoplasmic reticulum(ER) stress and calcium overload. CRT knockdown increased cell proliferation and reduced cytoplasmic vacuoles, which was associated with inhibited ER stress and paraptosis. Conclusions Our study provides a potential safe and effective agent for the treatment of liver cancer. Moreover, we have clarified characteristics of compound 4a-triggered paraptosis and revealed a unique function of CRT in paraptosis.