Poly(phenylene sulfide)[PPS] and its derivatives ; poly(phenylene sulfide sulfone)[PPSS], poly(phenylene sulfide ether)[PPSE], were synthesized and their thermal properties were investigated by DSC and TGA. In case of PPSE, the crystallization behavior was also studied by isothermal data from DSC and Avrami equarion. PPSE and PPS show high crystallinity, while PPSS is totally amorphous. Glass transition temperature(Tg), melting temperature(Tm), and maximum crystallization temperature of PPSE have much lower than those of PPS. On the other hands, thermal stability and crystallinity of PPSE were relatively higher than those of PPS.