In vitro β-lactamase inhibitory acclivity of 6-exomethylene sulbactam compounds (CH-120,130,140,145,150, 155) was compared with calvulanic acid, sulbactam and taaobactam. The inhibitory activity of CH-140 was stronger than surfbactam and davulanic acid against Type II, III, IV, TEM enzymes and stronger than tazobactam against Type IV enzyme. The inhibitory activity of CH-145 was stronger than sulbactam and clavulanic acid against Type I, II, III, IV, TEM enzpnes and stronger than tasobactam against Type III, IV enzymes. The in vitro antimicrobial activity of CH-140 and CH-145 combined with piperaciBlin and ceftriaxone was compared with the sulbactam and taaobactam against β-1actamase producing 31 strains. But Synergistic activity of CH-140 and CH-145 was inferior to tazobactam.