An audio signal processing method, comprising: determining a total quantity of to-be-allocated bits corresponding to to-be-processed sub-bands of a current frame; implementing primary bit allocation on the to-be-processed sub-bands according to the total quantity of to-be-allocated bits, so as to obtain a quantity of primarily allocated bits of each sub-band of the to-be-processed sub-bands; performing, according to the quantity of primarily allocated bits of each sub-band that has undergone the primary bit allocation, an information unit quantity determining operation for each sub-band that has undergone the primary bit allocation, so as to obtain a total quantity of surplus bits of the current frame and a quantity of information units corresponding to each sub-band of the to-be-processed sub-bands; selecting sub-bands for secondary bit allocation from the to-be-processed sub-bands according to a secondary bit allocation parameter, wherein the secondary bit allocation parameter comprises a sub-band characteristic of each sub-band of the to-be-processed sub-bands; implementing secondary bit allocation on the sub-bands for secondary bit allocation, so as to allocate the surplus bits to the sub-bands for secondary bit allocation and obtain a quantity of secondarily allocated bits of each sub-band of the sub-bands for secondary bit allocation; and performing, (SI 60) according to the quantity of primarily allocated bits and the quantity of secondarily allocated bits of each sub-band of the sub-bands for secondary bit allocation, an information unit quantity determining operation for each sub-band of the sub-bands for secondary bit allocation, so as to obtain a quantity of information units corresponding to each sub-band of the sub-bands for secondary bit allocation; characterized in that the sub-band characteristic of each sub-band of the to-be-processed sub-bands comprises a type of an audio signal carried in the sub-band and a bit allocation state corresponding to the sub-band, the bit allocation state comprising at least one of a coefficient quantization state of a corresponding previous-frame sub-band of the sub-band; wherein the selecting sub-bands for secondary bit allocation from the to-be-processed sub-bands according to a secondary bit allocation parameter comprises: determining a target sub-band set according to the type of the audio signal carried in the sub-band and the bit allocation state corresponding to the sub-band; and selecting the sub-bands for secondary bit allocation from the target sub-band set, where a sub-band in the target sub-band set belongs to the to-be-processed sub-bands. determining a total quantity of to-be-allocated bits corresponding to to-be-processed sub-bands of a current frame; implementing primary bit allocation on the to-be-processed sub-bands according to the total quantity of to-be-allocated bits, so as to obtain a quantity of primarily allocated bits of each sub-band of the to-be-processed sub-bands; performing, according to the quantity of primarily allocated bits of each sub-band that has undergone the primary bit allocation, an information unit quantity determining operation for each sub-band that has undergone the primary bit allocation, so as to obtain a total quantity of surplus bits of the current frame and a quantity of information units corresponding to each sub-band of the to-be-processed sub-bands; selecting sub-bands for secondary bit allocation from the to-be-processed sub-bands according to a secondary bit allocation parameter, wherein the secondary bit allocation parameter comprises a sub-band characteristic of each sub-band of the to-be-processed sub-bands; implementing secondary bit allocation on the sub-bands for secondary bit allocation, so as to allocate the surplus bits to the sub-bands for secondary bit allocation and obtain a quantity of secondarily allocated bits of each sub-band of the sub-bands for secondary bit allocation; and performing, (SI 60) according to the quantity of primarily allocated bits and the quantity of secondarily allocated bits of each sub-band of the sub-bands for secondary bit allocation, an information unit quantity determining operation for each sub-band of the sub-bands for secondary bit allocation, so as to obtain a quantity of information units corresponding to each sub-band of the sub-bands for secondary bit allocation; characterized in that the sub-band characteristic of each sub-band of the to-be-processed sub-bands comprises a type of an audio signal carried in the sub-band and a bit allocation state corresponding to the sub-band, the bit allocation state comprising at least one of a coefficient quantization state of a corresponding previous-frame sub-band of the sub-band; wherein the selecting sub-bands for secondary bit allocation from the to-be-processed sub-bands according to a secondary bit allocation parameter comprises: determining a target sub-band set according to the type of the audio signal carried in the sub-band and the bit allocation state corresponding to the sub-band; and selecting the sub-bands for secondary bit allocation from the target sub-band set, where a sub-band in the target sub-band set belongs to the to-be-processed sub-bands. determining a target sub-band set according to the type of the audio signal carried in the sub-band and the bit allocation state corresponding to the sub-band; and selecting the sub-bands for secondary bit allocation from the target sub-band set, where a sub-band in the target sub-band set belongs to the to-be-processed sub-bands.