In consideration of the close relationship of the clearance rate to the growth and development of filter-feeding mollusks, the joint effects of temperature (18-34℃), salinity (20-40) and pH (6.5-9.5) on the clearance rate (CR) of the juveniles of Pinctada martensii was studied using the Box-Behnken experimental design and response surface method under laboratory conditions, aimed at quantifying the relationship between the clearance rate and the above three factors, and obtaining the optimal factor combination through statistical optimization approach.The results showed that the liner effect of temperature, the interaction effects between temperature and pH, and between salinity and pH, the quadratic effects of temperature, salinity and pH on the clearance rate of juveniles of P. martensii were highly significant (P<0.01). The liner effects of salinity and pH, the interaction effect between temperature and salinity were not significant (P>0.05). The clearance rate model was derived, with the R² being 0.9950. The Predictive R² for the model reached 0.9284, showing that it could be employed to forecast the CR of the juveniles of P. martensii. The optimization results of the response surface showed that the optimal factor combination was 26.95℃/29.69/8.09, at which the maximum clearance rate, 1.4894×10^-3L/h, was arrived , with the desirability of 0.9886.