A polymer microsphere was prepared using stable crosslinker typeⅠ(MBA) and typeⅡ(PEGDA) labile crosslinker composite，typeⅡcross-linking agent has a decomposition temperature of 60-65℃ tested by bulk polymerization and the microspheres were prepared by inverse emulsion polymerization. The impacts of type Ⅱcrosslinkers to microsphere size and expansion properties were investigated using particle size analyzer，We also observed microspheres morphology before and after hydration combined with Scanning Electron microscope (SEM) . The results showed that the right amount of typeⅡcrosslinkers and MBA can reduce the primary particle diameter; microspheres were approximately spherical shape before and after hydration and the primary particle size was about 3μm，reunite effect was observed between particles after expansion；Unstable cross-linked microspheres had wide size distribution and swelled hardly at room temperature and the failure of type Ⅱ crosslinker resulted microspheres swelled faster after 60℃，Microspheres median diameter (D0.5) ranged from 13.94μm to 70.71μm at 19.5×104mg/L salt solution within 18h.