Objective:To investigate the effects of pamidronate on the osteoclasts activated by the polyethylene particles and explore the preventing effect of pamidronate on the aseptic loosening of prosthesis. Methods:The osteoclasts were isolated from the long bones of neonatal New Zealand’s rabbits and cocultured with bone slices to observe the effects of pamidronate and polyethylene particles on the osteoclasts’ resorption activity. First, the influence of polyethylene particles of different dosage on the osteoclasts’ resorption activity were observed;Second, the influence of polyethylene particles associated with pamidronate on the osteoclasts’ resorption activity were observed. Results:We found that three kinds of polyethylene particles(103/ml,106/ml and 109/ml)all can stimulate the osteoclasts’ bone resorption, and pamidronate of 10 μg/ml can inhibit the stimulation of polyethylene particles on the osteoclasts. Conclusion:Because pamidronate can inhibit the activation of osteoclasts induced by the polyethylene particles,it can be probably applied to prevent the aseptic loosening of prosthesis.