Abstract: OBJECTIVE To synthesis two PEG-dasatinib conjugates (JK120303 and JK120304) and get preliminary antitumor effect of these compounds in the K562 subcutaneous tumor model of human chronic myeloid leukemia. METHODS Dasatinib was derived with valine, then react with mPEG-dipeptide acid and 4arm-PEG-acetic acid to obtain PEG-dasatinib conjugates, K562 cells were inoculated subcutaneously in the right back of NOD/SCID mice to establish human chronic myeloid leukemia xenograft animal subcutaneous model, the curative effect was evaluated according to the relative tumor proliferation rate (T/C%). RESULTS Two PEG-dasatinib conjugates were synthesized, the efficacy of JK120303 (2.5 mg·kg^-1 and 5 mg·kg^-1) was better than that of dasatinib (5 mg·kg^-1) and the efficacy of JK120304 (2.5 mg·kg^-1 and 5 mg·kg^-1) was almost the same as that of dasatinib (5 mg·kg^-1). CONCLUSION The efficacy of PEG-dasatinib conjugate JK120303 is better than that of dasatinib and worth further study.