Abstract: In order to synthesize NaP zeolites by utilizing bentonite，the chemical composition of the bentonite was analyzed. As the main contents of bentonite，montmorillonite and silica were activated by alkali melt at 850 ℃ for 1h，and then the high active pretreated material was obtained.The optimal conditions of synthesis NaP zeolites were determined by orthogonal tests as follows：n（SiO₂）/n（Al₂O₃）=5，crystallization temperature was 95 ℃，aging temperature was 50 ℃，aging time was 2 h， n(Na₂O)/n(SiO₂)=1.6， n(H₂O)/n(Na₂O)=50， and crystallization time 9 h.The XRD and SEM analysis results showed that the products were pure NaP zeolites，the average particle size was 1 μm，and the Ca²⁺ exchange capacity （as CaCO₃） of dry products was 315 mg/g.

Key words: bentonite, alkali melt, hydrothermal synthesis, NaP zeolites