55 1800。 Official website shows that the postcode of China, the area code of Jinsha County, Bijie City, Guizhou Province is 0857 and the postcode is 55 1800. The first two digits of 55 represent provinces, municipalities and autonomous regions, the third digit 1 represents postal areas, the fourth digit 8 represents counties and cities, and the last two digits 00 represent specific delivery areas.