A wavelet embedded block coding method based on block bit-length is brought forward in this article. The memory occupancy can be reduced through four measures which adopted in the arithmetic in the process of coding and coding efficiency can be increasingly improved

respectively. The four measures mentioned above are: (1)LLn sub-band separate coding; (2)establish block bit-length chart in terms of bit-length

the bit-length is defined by the author; (3)save the space of memory by employing bit-length chart instead of using lists in the process of delicating and ranking; (4)swift search key blocks according to the construction of bit-length chart to overcome repeat scan and increase the coding speed. According to the experimental results

the arithmetic can reduce memory occupancy in the process of coding and increase the coding speed effectively

meanwhile

it can keep the high quality of PSNR.