The invention provides a low-cost production increasing method for weakening biodegradation and thickening of crude oil. The low-cost production increasing method for weakening biodegradation and thickening of the crude oil comprises the steps that 1, for a high temperature oil reservoir which is difficult to produce due to excessive thick oil, water flooding cold production development is suspended; 2, steam is injected into the ground, and steam huff and puff development is tried; 3, if the output is increased after steam huff and puff, steam injection development is continued, and if the output is decreased, cheap sewage flooding development is used; 4, sewage is subjected to still standing to reduce the content of oxygen and particulate matter naturally, and after still standing, ultraviolet lamp irradiation is conducted for the first time, so that degradation of the crude oil through water microorganisms is weakened; and 5, the sewage injection rate is controlled, so that water isheated by the oil reservoir, and natural heat sewage flooding development is realized. The low-cost production increasing method for weakening biodegradation and thickening of the crude oil has goodoperability, innovation and practicability and is beneficial to popularization, and a practicable method for preventing thickening of the crude oil due to strongly water washing in the low cost is provided.