Abstract: When the two groups of deep-sea samples taking from the Bay of Bengal were analyzed for OSL dating, we found that the samples are high in ²³⁰Th, ²³¹Pa radionuclides levels. After calculating the sedimentation rate of the samples with ²³⁰th_ex, ²³¹pa_ex and ²³¹pa_ex / ²³⁰th_ex, it is found that the results obtained by the three methods are quite consistent. The average sedimentation rate of C3 is between 16.2 and 18.2 cm/ka and that of CB2 changes between 10.3 and 12.3 cm/ka. Compared with the OSL dating data, the average of the sedimentation rate values is consistent. The OSL dating suggest that the two groups of samples may have experienced a process of sedimentation rate acceleration.